BIMBLE  I do understand working with limited resources. I think, though, it's worth noting that two reasons people post about this program are that they like it and want to be able to use it again, and because there is a subscription tier specifically for the desktop app. Those of us with that subscription tier who run Leopard really would like to be able to use the app again. Paying customers do tend to complain if they aren't getting what they paid for. ;)

Communication goes a long way toward customer goodwill, though, and it's a low-resource approach to staving off some of the complaints. The admin post is a good start, but I'd suggest also updating the app description with a note that the current version is not Leopard-compatible, but a new version is in the works. Also add a note to that effect on the subscription page.

At worst you might look into open-sourcing the client while controlling app access to your backend to keep it limited to subscribers. Offer app subscriptions as an incentive for people to submit code changes to you. I don't know if this would work with your current infrastructure, mind, I'm just offering it up as one possible approach to keeping the app development current with limited resources.  
(Version 4.2.4)

BIMBLE  I love this software. The interface isn't as scary as it looks - if you poke around on the web site there are decent examples that make it clear how you can customize the interface. Yeah, it might take an hour to get comfortable with it, but it's entirely worth the time spent. It's very easy to use considering how powerful it can be.

Once you're used to it, the interface is quite intuitive. It's a cinch to set up events for buttons, tie them to scripts, set up conditionals, and all sorts of controller tweaking. I used it to set up my Logitech G15 keyboard in an afternoon to control iTunes from the media buttons, and to set up macros for the extra keys that would only be active when certain games are the frontmost application (and much of that time was spent looking up AppleScript controls for iTunes and deciding what macros I wanted to program).

It helps that the interface is set up to make it easy to find the controls you want and to test them. Hit a key and the matching controller set highlights in the list of controllers. Select a controller set to see all its contents, and you can hit that button again to get it in the list. Then drag that button out to your "page" (the controller flow), and attach actions and tests to it. The on/off buttons highlight when you do so to show you how the controls will activate.

On top of that, the developer is very responsive. He answers support emails quickly, and frequently answers questions on the application's forums. This program is worth every penny I spent on it and then some.  
(Version 4.3.2)

BIMBLE  The Pedia apps are focused on their specific media types, which is why they're sold separately. Where Delicious Library has a generic template, allowing more flexibility within the same app for varied item types, Gamepedia and the other apps from Bruji have fields and options dedicated just to the type of item they track. That lets them gussy up the HTML exports and add fields specific to the media type (like whether a game is a collector's edition, and a section for walkthrough links and screenshots).

While Gamepedia is $18 alone, if you go to the developer's website they offer package deals - right now, 20% off if you buy two, $39 for three of the Pedias as a bundle, and $49 for all four.

If you want everything in one application, Delicious Library and the newer Library Pro are solid programs. If you want something more specialized by media type and don't mind having separate apps, the Pedias do a good job. Personally I like the Pedia approach better after trying several apps of this sort. I'd recommend trying them and the other applications out then making a purchase decision after that - the price points aren't very different when the bundles are taken into account.  
(Version 4.0)