I like Alternity, but it could stand a little cleaning up. You could remove a lot of the complexity from the system by just jettisoning the class system and making a couple skill changes.
Here’s what I’d do with an Alternity Second Edition. I’d keep the general skill basis and skill check mechanic with the differing quality of results for skill/half skill/quarter skill. Really the main rules are great and need little tweaking; the optional rulesets are where things start slipping.
Remove classes. They give you so little that it’s annoying – go “full GURPS” with it. Removes one chunk of useless complexity.
Remove levels. Spend XP as you get them. Removes a second chunk of useless complexity.
More skill points. Or cheaper costs. Definitely use at least the “Optional Rule Set 2” skill point values and, since you’re getting rid of classes, maybe just reduce all the skill point costs by one off the bat and tweak from there; maybe another one point drop for all broad skills. “But I always suck” is the main Alternity critique one hears.
Damage and hit locations. This would go a long way to fixing the armor issues. Top Secret/S.I. had a hit location/box system I really liked. You’d do this, fix the “lower number of mortal points” problem and the O/G/A weapon vs armor thing to be nicely symmetrical.
General guidance. There are a couple recurring pain points that are more about how you run the game than the rules as written. This includes “let any relevant skill work, with a 1 step penalty if it’s a real stretch.” Looking to stop a security computer on a starship from sending an alert signal? Yes, you can use Sec/Security Devices, Tech Sci/Juryrig, Computer/Hacking, or System Ops/Communications. Not “No, that’s not the perfect one.” Cover and stuff, it’s worthless currently, need a bit more focus on the firefight.
Consolidate and simplify. No separate GMG with rules players should know hidden in it. No “weapon accuracy by range modifier” special table. Make it so grenades work faster. Mainly look in the GMG, pull out all the tables, and then delete 99% of them as pointless cruft.
Psionics. Done once in the mainbook, redone in the Mindwalkers book, still sucky. Our party psis are always really weak – you don’t want to make them uber but currently you end up feeling sorry for them.
Computers. Are tarded. For what should be a sci-fi high tech game, the equipment and especially the computers are boring and stupid.
That’s it really, mostly a “delete all the exception stuff” rampage, and you’d have a terse and solid ruleset. More on specific new rules I’d like to add tomorrow…