I only knew one person who liked W7 better than W10, and that ended up being the result of him not knowing how to configure W10 in the same way someone had previously configured W7 for him.
I do have trouble believing W7 is faster than W10, because for the most part performance is identical (even on very outdated hardware), except in a few areas where W10 is objectively faster (like boot time). Could it be that your hard drive is getting full or is a lot more fragmented than it used to be? Have you done a W10 clean install?
I can imagine that some very old games may not run. Have you tried launching them in "compatibility mode"?
The argument that W10 is worse than W7 because the store has too few apps is, to put it nicely, strange. W7 doesn't even have an app store. Beyond that they both have access to the millions of Win32 based desktop titles. If any one is preferable in terms of software selection it's inarguably W10.
Direct integration of MS' services (like OneDrive) is likely the biggest reason W10 is objectively better. There are many many more.
I can understand someone preferring W7 for esthetical or other subjective reasons, but objectively it's very hard to substantiate that W7 is the better OS. Still, subjective opinions are important too. Either way, Depending on how you answer those questions, I'd recommend different courses of action.