Indeed jgodfrey, seen that you understand exactly what are the problems i want to explain you quickly how my system work,so maybe this can help other ppl too.
I setup a number of channels at the beginning of AREA of game (not entire game,because for example in a gdr sounds indoor are different from outdoor etc).
You may create a fixed channel (for example for a sound that never change,like a background music) and a MULTICHANNEL.
A MULTICHANNEL is dynamic: you choice the number of sub-channels it have and you may play any sound on it,the system will automatically find a free slot and play on it.
You may have any number of multichannel or singlechannel,so you can manage the sound based on what you really need.
If the slot its not found(all subchannels are playing)......here it come the trick.
Your suggestion yesterday made me think alot,specially your idea about priorities wich is smart in my opinion. But since i don't want sounds to be cutted off during gameplay,or un-necessary sounds being played (as you said too),i've ended up with this technique (wich of course,is always based on the cap that you also mentioned,a max number of simultaneous sounds limit ).
If all slots are busy(playing) then the system will replace the MOST OLD SOUND PLAYED(and not based on priority because in "real world" it's hard to choice wich sound will have priority,in my opinion),so my FRESHNESS system will just check wich sound in the slots it's the "oldest" and replace it. This should work because usually you introduce a new sound dynamically when a new event come,and this apply specially for looped sounds wich can become "old".
Plus: there is another trick: when you play a sound,you may set that sound to HIPRIORITY,and that sound can't be replaced in any case. So for example in a gdr if you have a water sound(looped) and you want it to be always heard,you just set it HIPRIORITY.
What do you think about that?
It's your idea about priorities that made me think about the freshness system,wich i think in "real world" it's more pratical,but of course i can tell that ONLY after i will test the final game (now it's still too early) with all sounds.
Today i will do a quick refresh of my old school books,seen that in 90's era they had very limited amount of channel and they made wonderful games.
I'll post a comment if i find new ideas.
Thanks for your help i appreciate it