As a new player... Arena is the most annoying since your score doesn't drop when you lose. Always got matched to people about 15-20% stronger (ex: i have about 650 overall, enemy have around 800 overall). Also how you lvl new heroes since you can't play low lvl maps, except for weekly dungeon?
Just enchant MP and HP regen on your items an you are GOD. Note that HP/MP regen are not /second but /fight, meaning after you kill a mob you get that amount of HP or MP. GREAT GAME :)
My heroes are around lvl 8-9 and from the chests (shop) or from crafting i get items that require lvl 15-20 because they give 15-20 stats. Also i have other items that gives more stats than my lvl. Please look into it. Remove the lvl requirment on items from shop and forge, or from shop give items according to lvl and remove forged items lvl requirment since that is the purpose of forge, to make better items.
I think it needs more difficulty options, because mobs die too easy :(
I got a mercenary (30 vit, rest all on agi) with leaf bow(gives 50hp for each tile betwen you and enemy) and managed to get 100% to pull enemy back on kill, not mentioning about 100 crit rate, about 200 or more crit damage, 50 or more hp regen . Since i 1 shot crit all with 5k+, melee mobs don't hit me at all and i pity the ranged ones...
As others have said a minimap would be nice... or at least an arrow pointing to boss. Overall is a great game.
 "Lionheart Tactics"){kind=icon}
 "The Enchanted Cave 2"){kind=icon}
 "Brave Tales"){kind=icon}
 "Loot Heroes"){kind=icon}