Hi, before doing some of those suggestions, I suggest you to read this, just to avoid any problems:
(
DO NOT LINK) h t t p s : / / openarena . wikia . com/wiki/NOTTODO
EDIT: Check also this, if you have suggestions to do regarding to maps: (
DO NOT LINK) h t t p s : / / openarena . wikia . com/wiki/Maps. There're links to their topics, so you can drop your suggestions there instead of just saying "maps sucks" and nothing more.

Really you can only be disappointed with Joki. only about the section in which he posted this one , since there is a specific topic about suggestion ;-)
- add selected cvars from the OSP-mod like:
- referee-system
- complete control on client cvars-range (like server_timenudge_max -20: if a clien uses cl_timenudge -30 it will automatically change to -20 to get in allowed range)
- timeout-system
- cg_enemymodel
- more custommizeable HUD
- alt graphics especially for those hard to see grenades
referee system , control over client cvars range ( control over cl_maxpackets, snaps , rate ... I've proposed also to lock cl_yawspeed and cl_pitchspeed to their default value but they can be controlled server side to avoid scripts abuse .... conditioned delag activation according to the player's real ping - delag forced to 0 if ping is <= 50 ) , timeout system were all proposed in that topic and all WOULD NOT apport real changes in the gameplay ( even if OAX has introduced some changes , adds to the vanilla gameplay )
Ive proprosed to implement the CPMA SuperHud ( which should come as an independent system and its activation should be managed by a cvar like cg_enablesuperHud 1 ) to have the possibility of customizing HUD which doesn't mean necessarily to not have the default HUD.
Enemymodel , brighskins/PM-like skins and alt graphichs for some weapons to increase general visibility and general performances are also a good idea else we will continue to blame pro-like and pseudo-pro-like players that still want to use vertex light and their lego-quake-style config.
maps like czest1dm, fan, oa_dm5 (its just way too tight that you can dodge at all, leaving the map to turn into a a total spam-as-much-as-you-can-luck-fest), oa_pvomit or suspended and also most of these plain HORRIBLE designed ctf-maps are no advertisement for openarena at all. luckily there are a few good ones to name oa_rpg3dm2, oa_shine and maybe oadm4ish.
...
- change the audio for "pick up armor", "pick up quad/powerup", "power up spawned" to louder, unique ones, that are actually hearable. suckt to have to play with zzzq3sounds.pk3 all the time
I vote for removing cbctf1 , czest1tourney , fan and suspended : gameplay is really horrible ... I do not agree with you about czest1dm , oa_pvomit which are still acceptable.
About oa_dm5 and dm6ish : the OA071 versions are better than newer one . The old oa_dm5 looks really worse than newer but as a paradox ( or not ) I found it more playable than newer because general visibility was better without having to increase gamma and *overbrightbits . The retexturized version looks better but it's terribly darker. The same for old dm6ish.
This thing about the audio should be revised too because you can see also in some ( not so few ) videos that many players uses some q3 sounds ( eg ... in the latest I've seen I can hear clearly Keel and Xaero footsteps sounds )