Level 29 mana troop has 26% attack, 18% defense, 19% healing, and 15% mana
A level 50 legendary troop has class depending stats, but using barbarian/druid as an example would have 39% attack, 29% defense, 39% health, and 15% mana. Definitely an upgrade. No question about it.
The full class bonus is 11% attack, 11% defense, and 15% health, so small bonus but still helpful. It also comes with an additional bonus (similar to passives).
At level 25 those numbers are 23%, 18%, 27%, and 10%. So that’s roughly comparable. Slightly less attack, no healing, but huge health, and big mana drop.
Using every single feeder I have, I can get one troop up to level 49, where 15% mana comes. That’s a rough breakpoint. It makes it hard to recommend anyone use a current mana troop to convert, because if you only have one, it’s unlikely you’ll have the feeders to get up to level 49.
I should note that to get to level 49 it would cost 40M food and 40M iron in addition to 133K xp (I started with best troops so this was not the most efficient way)
That 10 to 15% mana boost is tough.
10% is enough if you have a costume or a talent node for average or slower heroes. But fast heroes need 15%. You need a little bit more to really get a value add tradeoff here.
I see two paths for myself, both involve keeping my level 29 mana troop.
1 Sacrifice my second best troop. I generally have a level 23 troop for each element. I can do a little leveling and sacrifice that. I lose the ability to have a second fast hero, but this keeps my main troop and gets the legendary troop the highest.
2 Sacrifice the crit troop. I have crit troops in each color ranging from level 12 to 20. I could level them, and sacrifice them. I essentially don’t use them today, so even a 5% mana boost is a bonus. That new troop would become my second best troop (and eventually my best one).
It will cost 19M food and 48K xp to get my level 12 crit troop up to 27 to be sacrificed. That’s a lot, but in the long game of E&P this is probably the better play because I’m not losing anything I use today.
The hardest part is picking the class. What works today won’t work in the future. SG can monitor which troops are picked and release heroes in new classes where the least common troops are picked. I won’t worry about this too much as you can’t plan for it. If i happen to get a new great hero, I won’t worry that I don’t have the class troop for it.