Dryad Strike is a pretty good map, it's usually fast-paced and very fun to play. I understand that most units are based of melee Wc3 (with exceptions where their abilities would not be useful, such as Far Sight) and, as far as I'm aware, even their attack damage and armor values are untouched, with only their attack speed and health modifier to bring a much faster bloodshed compared to the original melee. I think this is a good starting ground for balancing, as you avoid touching unnecessary variables, but I still have a couple of balance concerns I wanted to share.
As a disclaimer I do not claim to be a good melee player whatsoever, nor a great player at this map either, so take this comment with a grain of salt. So far I've only played 20+ games with random hosts on Bnet, with my winrates of 7-6 as Human, 3-1 as Orc and 4-1 as Undead and 0 games as disgusting dryad spamming Night Elves. I've mostly learned the map by playing Humans and tried a couple of very questionable builds, like building around Paladin since level 1 through items and what not (works okay-ish in late game, just don't rush items in early game, from my experience at least).
That being said the map's name is misleading and should be called Dryad Strike instead, due to the amount of NEs and them always placing lots of Dryads and usually winning to be honest. Whenever my allied players are NE, I tend to compare the amount of Dryads they've built to the amount of Dryads the enemy has built and the win/loss tends to be determined by this rather accurately. Without going further into the shitpost, since they're magic immune and have slow poison they essentially counter both casters and attacking units, on top of which they also have abolish magic. As far as I know there's a good reason why they've been in melee meta for a while too. I would seriously consider reducing their DPS output since they already fill the role of support via slow poison and abolish magic.
Another unit I have serious issues with is Lich and his Death and Decay at level 6. In retrospect, I believe I've mostly lost by trying out questionable builds, or when I play "good" builds where I build solely to counter the enemy team, there's not much to do against Dryad spam (NE) or Lich (UD) hitting level 6. That guy alone destroys most of my armies, and his power only tends to go up as Death and Decay has a solid AoE and as spell damage it ignores armor values, so upgrading armor will not help against this. It's almost impossible to build around this, even my best counter so far, Mountain King with Storm Bolt really depends on the AI. Even if MK focuses the Lich, a smart Undead player will either get Banshees with AMS or simply get the item that blocks spells cast on the hero. The Frost Nova also oneshots Footmen if I'm not mistaken, though I suppose as an Intelligence hero you can't really build items for them (since there's no cooldown reduction or amplified spell damage or anything of the sorts in melee wc3, and therefore in this map) so I guess it makes sense that it deals so much damage. Death and Decay on the other hand seems way too good without any counterplay that essentially wins late game.
These are the 2 top balance issues I have with the map. I can talk about other things, units being overpowered/underpowered but I don't think anything comes close to the two examples I gave above, mostly due to the lack of counterplay in many cases. Flying Machines seem way too weak as in melee wc3 they're balanced around 1 food cost AFAIK which is not an issue in this map, yet their poor stats carry over. Gryphons might be dealing too high DPS considering they AoE rather easily with their upgrade, and they're pretty cheap too, as they are in melee. That is until they encounter Dryads and ignore the front line which they're supposed to counter (Knights, Abominations, Taurens and Druids of the Claw respectively per race) and start focusing the ranged heroes attacking them, only to get baited into the Dryad trap and have their private parts wide opened which they did not sign up for. The Spellbreakers might be a bit too versatile, being rather useful in most scenarios even with limited amount of casters on the opposing team, etc. I mostly talk about Human units as I have most experience with them, so I can point out those that are too good or weak, as I try to be honest with myself and find strategies that are overperforming too. Being able to build around some Heroes seems fun, though I question the usefulness of some Intelligence heroes, such as Blood Mage or Archmage. Their Flame Strike and Blizzard respectively seem to be overall outperformed by Thunder Clap MK (considering the AoE slow which seriously counters Vamp Aura/Ghoul spam, cheap Human units like Knights/Footmen/Rifles, strongest Orc units like Tauren and their Pulverize, etc.) who then also scales really well as a front line and damage dealer in late game. In my experience, MK is probably a bit too good; being able to deal with Hero strats through Storm Bolt and Bash, dealing with ground units via Thunder Clap while also becoming a tanking powerhouse through Avatar and a couple of items. Orc's Tauren Chieftain does a similar job too, comparing to him MK looks fine but compared to other Human heroes I'd say he outperforms them overall.
The items are a really fun addition, though I think the Orbs need to be rebalanced. There's really no reason not to pick Orb of Corruption over anything else; Why slow/purge/poison a unit if you can simply kill it faster? Why gain +5 splash damage from Orb of Fire if you can get ~+25% DPS increase on single target, not just for your Hero but for other units too? The Orbs are rather expensive too, assuming Orb of Corruption gets nerfed, I'd say the orbs are never worth it unless you want to make a melee hero attack air units. Due to their high cost, I'd suggest buffing the other Orbs and potentially slightly nerfing Corruption in order to maintain balance.
It's good to see that Agility heroes were taken into account; you can't get as much Agility as you can get Strength from items. While I respect this careful approach, from my experience mostly Strength heroes dominate the arena as a result when built around; Dreadlord, Mountain King, Tauren Chieftain and Paladin alike. I have yet to see a scary Warden or Priestess of the Moon (though her Trueshot aura is amazing), as I've only seen decent Blademasters and Demon Hunters performing as your "expected", high DPS Agility heroes. The 4 mentioned heroes each have their really powerful abilities that make them so strong; Dreadlord gains 50% Life steal, MK has lots of CC and Avatar, TC has CC and revives himself, and a well equipped Paladin uses Divine Shield at ~15% health and then Life steals back up to ~70% health during that time, all while supporting allies through any and all of his other abilities.
All in all Dryad Strike is a really good map, I just wish I'd play against fewer Dryads and had more counterplay against them and Lich's Death and Decay. I think in general it would be cool to have an item or any other form of "neutral research", if that's something you ever plan to have, where we could grant spell damage reduction to our units, so that the spellcasting heroes have counterplay instead of being balanced around a spot without one.