There would be very few, if any, that you couldn't. There is a difference between strongly acidic and slightly acidic. Slightly acidic should be able to grow anything, most plants won't care or will likely enjoy it.
I just read an article on the crypt pages that says "karst" crypts like C. aponogetifolia and C. affinis don't like soft acid water. I am willing to bet slightly acid conditions won't hurt anything.
Also, common knowledge says that some vals won't tolerate it. I doubt it.
HM doesn't grow well in AS? Coulda fooled me. Mine is growing like mad and it looks real good too. The only plants that haven't grown outstanding for me in AS were bacopa caroliniana and lobelia cardinalis. Both grew in with curled leaves, but nothing else has done this. I'm not sure, however, if this is because they don't like the conditions provided by AS or if I'm doing something wrong.
My HM is starting to grow like wildfire now. The plants that melted due to the AS are still dead pretty much except the R. rotundifolia. My kH/gH isn't at 0 anymore....closer to 1 now, haha. But *new* plants I add in are doing well.
My lobelia is doing better and I got rid of the bacopa caroliniana. Everything else is doing outstanding with a Kh/Gh around 3. ph ~ 6.2-6.3
Make sure you trim your HM once it starts growing for you. It will start to go the route of glosso, by growing over itself and then old leaves start to get algae and/or slowly discolor.