Just a few random ideas here...
1st thing, is ... Sometimes games get neglected because you don't think off the top of your head "oh I want to play that". Unless you have some layout where all of your games are visible, it's hard to get a good overall look at your collection.
So my first suggestion is with Daisakusen - since that already stores all of your PCE game, can we possibly look at some kind of java pop-up grid, just showing cover art? Then if each screen has 5x5 or more games, and you can click along.
So, just putting that out there.
Secondly, another great site, PCEngine.co.uk, isn't in any kind of database, just static pages. It would probably be of benefit to have a searchable database, though obviously it depends whether Paul has the time/means/inclination. If you do though Paul, I'd be prepared to muck in.
Thirdly, it might be good to have a similar thing for the Megadrive, but I'll post that on Sega16.
So hope this is taken in the right way ("suggestions" rather than "meddling" say), but I thought I'd see what everyone else thinks.