You can get a list of wanted players from the npc in the pd or by just checking scoreboard.
Then you can do /loc (id) to see their precise location with distance how far they are from you.
Most of the time chasing one particular criminal isn't worth it, it's much better just to check chat and see where the closest orange or red crimes accur, go there.
Regarding the OP's suggestion:
Make it above X cops core, I'd say 8 or 10k.
Make it have only X slots.
Make it have better vehicles, more armor or whatever really, just so you are a big armored force and crims have a hard time wrecking with you.
Pay can be increased, but doesn't matter too much.
Score increase per action would be really cool. Just as a reward for getting this far.
Currently regarding the bases we already semi have them. There are the FBI bases around cities, like in western LV, in one of the lower garages in LS, North from Market. You can find the FBI black ranchers there, you can make it be a base as well for the highest of the highest cops.
Other cop things that should be added:
GtaFreak already suggested this via general on discord, but make it possible to buy tazer and other ammo to max from the cop shop.
Add sawn off and other weapons to the cop-shop.
Make it possible to turn your personal vehicle in to a cop vehicle for a fee. Some say it'll be overpowered with infernuses, but cops already get infernuses, it would be a bonus for Rank 10's.
Make it possible for high scored cops or something to create a vote to demote people from being a cop for X time. Could be extra security layer in the case of an admin not being online. You all know how it is with the new guys just killing yellows, shooting suspects that are being cuffed, ramming you whilst you chase after someone, or just sit in prison afk all day accepting bribes.