If you're planning on upgrading/getting to endgame, you're going to have to play alts anyway.
I'd say start them early, and only play them when you have additional time. (After your 200 EP is gone.)
Just saying, I do not feel any meaningful difference when playing alts now that I am Lv. 55.
5% Really is not that much.
PS: You play this game for fun, if you feel like starting with an alt, just do it.

