I already have a Switch, but I bought one sooner than I had planned. I was originally waiting for a revision as well.
The main issue with the Switch right now I think is the battery life. That's not really Nintendo's fault though. They already put the biggest damn battery in the thing they could. It's more a problem of battery tech and until some 3rd party makes some breakthrough, then Nintendo, smartphone designers, and everyone else is stuck with crappy battery life. It would be nice if this is a breakthrough that happens within the next year or two and then Nintendo is able to utilize that in a revision 2-3 years from now. I wouldn't hold my breath though. More likely, battery life will be increased by improving efficiency and power draw elsewhere. Replacing the X1 with Nvidia's next gen chip would help, for example, but it may be a while yet before that's available for consumer electronics.
It could also stand to be slightly smaller, which would be possible with better battery tech and a more efficient cooling system. It's not a bad size now, but anything to shave a little off the weight is a bonus for a handheld system.