Cwa Effects On Wilderness Performance

So the standard excuses for doing CWA are:
- Clean fights with no crashers/randoms
- Members can practice without losing rune sets/hard to get equipment

Well, that's what our PK leader told me 3 years ago anyway.
Basically the assumption was that if we "practiced" in CWA, we'd get better in the wilderness.
After 3 years of "practice", I personally don't think it's working very well.
This might be because CWA doesn't work, or other reasons, or a combination of both.
For example, returning slacks a bit, something CWA can't help.

Eight years ago there was no CWA to practice in.
If you wanted to become a top clan, you did everything through the Wild.
The top clans of the day - DF, VR, RSD... they all were established in the old Wild era.
Have we ever seen a top 10 contender that came from CWA?

Is secluding to CWA when you can't compete in the wild the right way to go?
Is it possible to use it to one's advantage, and actually benefit in some way from it?
Or is CWA nothing but a hindrance to a clan's growth and progress?

Question: How does fighting in CWA affect a clan's performance in the Wild?

I want your thoughts - how should clans consider and use the arena?