Coling, that's a typical reaction to new software or new versions of the same software, I am myself like that. Unfortunately we have to move on, the sooner the better, as the BetFair's clock is ticking.
Actually, 20 markets refreshing simultaneously is a lot. There is no way you can refresh them even once per second without exposing yourself to fines for excessive requests. In fact, I'm surprised that you still haven't been contacted by BetFair with regards to this.
MF pro 7 will limit your requests in order to keep you on the safe side, that is why you perceive it as slow.
The good news is that
MF Pro 8 will not have these limits, as it is based on the new API-NG.