I'm just sorta spitballing theorycrafting stuff. I won't probably have a chance to play it out myself with a group, but I was looking for feedback/number crunching from forum-readers that would be so inclined.
So my thought was 'what if I tried to get rid of the super spread of 1-20 combat gear (and some of the associated mechanics), and do away with some of the aspects of 'wealth by level'. How broken could things get?
First, I wanted two stages of gear, basically boiled down to 'standard' and 'elite'. Functionally weapons/armor would have two 'levels' roughly level 10 and level 15.
By level 10 I mean, take the listing of the gear at roughly level 10, that's the new standard that nearly everyone uses. So even if you have a brand new level "1" character? They use level 10 gear. (10-ish).
"Elite" gear would be the level 15 (roughly) stats. Characters level 1-12 or so can only usually get 'standard' (level 10) gear. At 13 and above (or so) you can get Elite gear. At high end you're still only looking at 100-something thousand credits for a gun/armor/etc.
Now to avoid kiddos getting pasted at level 1 even if wearing level 10 armor, all chars, npcs or otherwise, get base hitpoints/stamina as if level 10. This number doesn't increase until they hit level 11, and then increases as normal. Roughly everyone starts at a 100 something hitpoints/stamina total, with martial classes having more.
If they have a class function that gives them damage, that also gets calculated at base level 10. Solarion weapons, caster level, etc. However, a class retains its normal progression in terms of ability/etc unlocks. So while you can cast your level 1 spell zapper and it does level 10 damage, you don't get access to higher level spells until you actually reach that level. Damage increases as level increases for these abilities. This also applies to heal spells/etc.
Weapon specialization dmg if applicable remains level based as normal. So A level 5 guy does +5 dmg to his base-level-10 weapon/etc.
Otherwise I envision CR being as normal, since they have the same damage output and capacity to resist relative to PC values.
Generally the cost factor difference between a level 10 and level 15 piece is x5. So the level 15 piece of same time generally costs 5x as much as the level 10 piece.
At the same time I don't see too big of an issue with PCs maybe getting elite gear early since the difference between 10 gear and 15 gear isn't as significant. Its an increase sure, but not usually a 1-hit kill scenario at any point. Things get a little wonky with some weapon classes scaling, but otherwise the level 10 and level 15 stuff is usually like +6 to 10 dmg max compared.
Some things I haven't crunched yet:
1) If I don't increase BAB can level 1 guys in level 10 gear even hit each other? Would that require the new BAB to be also based at Level 10 to even it out?
2)If you basically have gear that costs 25k and gear that cost 125k or so, and you start everyone at Level 10 wealth, do you still need a wealth cap? In terms of gear you might have millions of creds of stuff, but you only get mechanical benefits of gear level 15 or so.