Pricing and pricing only. The flat fee is one of the biggest killers. $0.30/per makes it near impossible to offer certain features and 2.9% is decently high (and that's before you turn on any other services). Instead I'm able to get ~2% (varies by card, some are higher, some are lower, but I'm just paying the interchange fee + a small percent to the processor) and zero flat fee on the transaction.

EDIT: Just to expand on what I'm doing, it's software for food festivals where people pre-load their accounts with money and then spend it at the vendors. It means we only need in-person CC terminals in a few places and vendors can use their smart phones to charge someone's account. It also means all transactions go though our software and the festival can take it's cut. Without this vendors would provide.... creative records of how much they sold (festival takes X% so if the vendor can hide some sales it can keep 100% of those sales). Because of this there isn't a ton of room for more percentages/flat-fees to be taken out. If someone wants to buy something and needs 1 more dollar in their account then we give up over 30% to Stripe. Even on a $5 charge we give up close to 9%. If I can get rid of the flat fee we could do a number of things like just linking a card and charging it on the fly with every purchase instead of first loading money onto your account. I'd be killed with fees if I did that with Stripe since we are talking about $2/3/5 items (it's a food festival, the portions/prices are small so you can try a bunch of things). Also things like "auto-reload if your account dips below $X", with Stripe I'd need to make the reload amount minimum decently high to avoid taking a bath in fees.