Well so for starters I'll link to an older spreadsheet I made with the approximate rankings of towers me and my two friends came up with:
https://docs.google.com/spreadsheets/d/ ... sp=sharingThe page labelled Nick (2nd page) has them ordered in tiers instead of just best to worst, which possibly has higher value than the first page.
Anyway, going approximately from the lists we made and also from what I've experienced since then, I'll give a fairly thorough list:
Tier 1s:- Small land mine has a niche build which is pretty punishing to get wrong and falls off extremely hard. The amount of push you are able to get while doing yolo landmines is only marginally better than other extreme yolo towers like Aqua Spirits which gives me cause to think they are underpowered.
- Gnoll Warrior, Peasant, Colt, Proton these are all towers which are only usable in general as a meat shield for something like a Grizzly to be able to hold 1 or for delay in a cross. To me this basically says it is a throwaway tower which warrants removal or rebalancing.
- Hatchling as a Fangtooth is one of the 150g value level 1 holders, which earns itself a margin of respect from me, but still the tower feels pretty weak and personally I see no reason to ever build the Defiler. Perhaps it's just me but I think the little guy could use a little TLC.
- Tuskar if upgraded to a Spearman can provide a margin of utility as pierce dps for wave 10. Otherwise the tower is pretty crap, but still not as bad as the above mentioned towers.
Tier 2s:- Servant needs so much value to be reliable at holding even the most basic rounds that you are giving up income and trying to make up for it with slave trade gold which just doesn't equate. It means you can't send with your team and you aren't even a strong holder as a result.
- Novice is similar to the Fangtooth when you make him a Crusader and not the worst as far as light tanks go but there are just so many better options that you would pretty much never choose to build Crusaders. Very lackluster tower.
- Frost Wolf can allow for some amount of yolo when built as Pandaren but being a medium armored melee tower with 800 health makes him drop off pretty bad imo. All melee tier 1 and 2 towers kind of suffer from this though.
- Ghoul is another Fangtooth, not much to say. He has a small niche but just feels under-loved.
- Carrion Spitter gets outclassed since there are so many pierce towers that provide better bang for the buck. Pierce isn't a rare enough damage type for this tower to be of much use.
Tier 3s:- Sentry I see Nightsabers built quite often but I just don't respect them as a unit. It seems to take so much more value of them than other multi-hit units to get the same job done. This might just be me but I never ever succeed when I do Nightsabers.
- Harpy is one of these units with a niche but it's so narrow. They are good on 10 but that's it. After 10 you may as well sell them because 35g is worth more than they are on every non-boss round.
- Watcher is a unit I hate to love. I want it to be a pseudo-Elite Archer so badly but it isn't. It isn't at all. It's not even close unfortunately. It can provide some help to units like Spawn of Dragonand Orc Warchief that frequently leave units with extremely low hp so it's not completely without a niche but I still think it's got way better alternatives that pretty much make it a non-factor to 95% of builds.
Tier 4s:- Tempest is almost a decent tower but then Leviathan is so immensely crap that it just can't stand up to any other option. It makes non-siege towers look good on 17 by comparison. I would personally recommend nerfing or completely removing the ability and giving it an actual attack speed. Also the range is garbo but that's less of a problem.
- Priest feels like it should be a good tower in builds that utilize small amounts of high-value towers but in my experience it just isn't worth how much it costs. I think either the mana cost is too much or the heal is too little or some combination of both.
- Outcast feels like a t5 but it's a t4, which is just weird. But among t5s it's very underwhelming. I think it needs a higher proc chance on the Forsaken One's ability and it would probably be ok.
Tier 5s:- Zombie falls flat compared to other t5s. The aura is not good enough early so it can't hold early rounds but then its hp is not good enough for it to survive late when the aura actually becomes useful. Also the aura radius is too low. Even just giving it more radius would probably be enough to make the tower worth it.
- Apparition in my opinion is just too expensive. It does have a decent niche though but I'd personally advocate some nerfs to the tower and reduce the cost to more like 200.
- Komodo upgrade has never impressed me but I don't have much experience with it. I might just be missing out on his better side.
Tier 6s:- Seer of Darkness is too expensive and gets outclassed by the alternatives in my opinion. I'd almost always prefer to reroll for better magic damage because there are a lot of better choices. Either lower price or better ability would be required to make this tower worth it in my opinion.
- Moon Guard I always used to think it was more or less the same as Orc Warchief and Spawn of Dragon, but it can't even measure up to the Minotaur in my opinion. Building a normal/heavy t6 to hold 7 and 8 should not be as hard as Moon Guards make it. Not even good on wave 5. Too many weak waves to be a good tower.
- Steamroller has always just struck me as a worse Neotank, which these days isn't even the top of his class anymore. Mutants and Ambassador of Darkness take the cake for siege nowadays, and I'd even take a Greymane or a Goliath over an Assault Tank. Seems like the ability is just a bit too cheesy. Should be replaced with something more relevant.
- Young Frost Dragon is weird like the Seer of Darkness, where it's a long-range magic dps unit with a tank ability. WHY?!? Give the Azure Drake a more dps-oriented ability and preferably a better attack speed but even just a more appropriate ability to its role and it would be at least manageable.
Those are my opinions on which towers deserve upgrading. The rest have enough of a purpose, and obviously not every tower has to be the "best in its tier" in order to be a balanced tower.
Edit:
I'll also bring this up here, I think it's stupid that Raiders and Gateguards are so close to the same unit they are virtually indistinguishable. Why do this? Also just noticed this in my research for this edit, Raider is the same cost as Gateguard with two disadvantages and no advantages. Lower attack range and less hp on both regular and upgrade. If there hasn't been a better idea made for them and they have to fulfill a similar niche because the builder needs a normal/heavy medium-duty tank, then let me suggest an alternative:
Raider: 85 g 1 food
Damage: 30-34
Speed: 1.2
Range: 100
Health: 325
Ability: None
Blood Raider: 135g 1 food
Damage: 90-96
Speed: 1.4
Range: 100
Health: 700
Ability:
Subterfuge Raider has 20 mana. Regenerates at normal rate (1/s). Ability triggers if Blood Raider gets the last hit on a creep (non-boss). Creates a copy of the target creep as a minion for the Raider. Minion has 20s lifespan. Ability has 15s cooldown, 20 mana cost.