My suggestion would be 300 EVs so in total would have 600 EVs, and we cant use Items. I believe 400 EVs are ALOT from 252 to 400 .... why not 300? still hard but not as hard.
Again, indeed its a buff overall, but i believe its not worth.
As it is now, where u have 60 bosses, but only 20 gives you decent cash + decent rewards + they are located in places not hard to reach. Because if u change dificulty, buff slightly the bosses that most ppl do even do, and nerf those that everyone does, u still think it will be a buff? Again Overall might be, but in reality it wont. To do all 60 bosses, which they are spread the whole map, takes time + harder matches will imply more time, AND since bosses got buffed hard, only stall/some strats will be effective to beat them. All of these things will lead to waste time, as it is now it takes almost a full day to beat every boss.
Suggestion: Either Buff rewards by removing some bosses (lets say former staffers, anything) so u keep the overall cash, with less bosses. Change Locations so everyboss is located in a City/Town or near by. And i think that we could use the House located at Lavander Town, to implement there some new bosses (Champions of ea Montly Tournament) but all gather in the same place.
PS: Plz remove the Mecha Mewtwo, i belive is stupidly strong