Now I don't know where to put this so I'm just gonna put it here. What I was thinking of was a third mode to Natural Selection that was a combination of combat and classic.
The general idea is to have both exp and res at the same time. The way this would work is both marines and aliens would get a small amount of exp and a small amount of res for each kill. The res would slowly fill up and then go over the cap (which would be significantly lower seeing as exp will be used for lifeforms and upgrades). In the case of marines if would go to the pool to be used by the commander for upgrades.
Gorges would receive a third of whatever is coming in but the kicker is that the amount of res being issued from kills would be low enough to still require a need to capture and protect resources. Aliens would be able to get lifeforms at will however upgrades would be limited by the chambers dropped at the time and the number of hives thus preventing super fades etc too early on.
On the marine side it works basically the same way, comm uses any res coming in to buy access to the tech tree and build pgs etc whilst the rines buy their own weapons and heavy armor etc. using exp. Structure costs would be tweaked to require a need to hold resources.
Overall exp would not be lost should a fade and etc die however it will still provide the enemy with exp and res, making them stronger thus giving you the incentive to try harder not to die. Same applies to marines.
One problem I can think of is that at the start if the gorge life form was restricted to exp aliens would be at a disadvantage at the start as rines could just camp at first to gain a quick advantage, unless the gorge life form was the only one that could be bought using res or experience points. Exp. if you have it, res if you don't and nothing if you have neither.
This could provide a better learning environment for new commanders as they wouldn't have to concentrate on dropping weapons/jp/heavy but just buildings + med packs + catalyst packs, mines would be like they are in combat.
Contrary to combat on spawn rines would be able to rebuy hmg/gl (revert to shotty) Should they want to switch weapons and also weapons would not be dropped on the ground on death. Aliens would also be able to swap between alien forms and only pay the difference/recieve the difference within say 20 seconds of the completion of a life form evolve should they accidently gorge instead of fade etc.
As far as maps go all you would really need is a server cvar to enable this mode and for the admin to use classic maps as it would fit. Sure this would encourage ramboing but in the end you would still need teamwork to win.