I think its quite good balanced. Erebus seems to me a bit to strong but changing envoirment settings also changes the whole balancing of the game.
The problem is like in every game as mentioned above that everybody has his different view on the game and how to play. I remeber another game I do not want to mention here since its not from StarDocks It had about 6 patches. This were released in a period of about 1.5years. Nearly every patch was a balancing patch. And I recognized it twice in the game that there are real changes. And now in the latest version I still find some inbalanced types and skills. Which giving you an advantge to other players. But maybe this is no imbalancing problem. Maybe its just a problem to be prepared or to use the right strategy.
DPS items (Gloves) are underpowered, Sednas Yetis are underpowered, Qots and TBs switch time is too long, Favor items are fucked up a bit, Artefact Potions are underpowered, Regulus mines and UBs Spit have too huigh range, Minion EB is too strong (Bite & Nightxrawlers). If you correct this, it might be a bit more balanced. But dont forget the fucked up towers, which dont scale after lvl 10 (get farmed by evry DG), the death timer, and exp upgrade, which all are senseless.