I have also had the opportunity to replay some titles that I played a lot when I was a kid and now I find them boring.
Maybe it happens that way because when we were kids anything that shined and was new impressed us a lot, but now as adults and with a different perspective of how we experience things, maybe they don't seem as amazing as before.
It's a bit risky replaying old games for sure. If you end up disliking them it may ruin the image you had of them forever. Luckily I don't go back in time that often.