Do mega-evolved pokemon revert to their base forms upon switch-out?
Late response here, but they do not. I believe they only revert when they're KO'd (fact-check me on this) or the battle ends.
I have another question. What are the useful natures? I know each one has some use, but some are just garbage, aren't they?
If I could have a list of the potentially useful natures, like Modest, Timid, Jolly, etc., it would be appreciated, so I can get Syncs of each of those natures.
Personally, I only exclude 7 of the 25 natures: Gentle, Lax, Bashful, Docile, Hardy, Quirky, and Serious. Those, in context, would be the "just garbage" natures.
The rest, well...each nature can be useful in some way, but the least situational natures are: Timid, Jolly, Hasty, Modest, and Adamant on the offensive side; Bold, Calm, Impish, Careful, Relaxed, and Sassy on the defensive side (although Impish and Careful are questionable).
Disclaimer: This is my opinion. Feel free to disagree.
Also, a question of my own: anyone have a good set for mixed Lucario? I have a Hasty max speed Luke and I don't know what to do with it.