So according to Gw2 Efficiency, which is not the be-all-end-all of sources, but still the best we have available:
Not even 5% of registered users have actually killed Qadim "2" (in Wing 7).
Dhuum has been done by ~7% of the playerbase and Qadim "1" (Wing 6) has been done by ~5.5%.
Obviously its only for registered users....but considering statistical projection (which Efficiency provides a good enough sample size for), It probably draws a pretty realistic picture for the entire playerbase.
Anyhow, the point to this is, that raids are played by a very, very small percentage of the community.
Personally I think this can be "improved on" by making Raids ACTUALLY profitable. Like a genuinely good gold farm.
Generally speaking, people in this game go absolutely mad on open world farms.
Dragonfall, SW or old Istan are very popular when it comes to gold per hour farms. And people don't really do them, because they are particularly fun, but because its good gold with minimum effort. Like those farms award between 20 and 25 g per hour.
To be fair, Raids ARE better for g/h, but its very disproportionate to the amount of effort it involves.
The general consensus from what I have seen, suggests that Raids award ~30ish g/h if you dont wipe and clear each boss/encounter in ~5ish minutes.
And that actually is a pretty high standard for uninformed or non-hardcore players. (Not bashing on anybodies preferences here; this is a perfectly acceptable way to play the game).
Especially If you are not part of a raiding static or guild and have to do it in a "less optimized" environment (basically meaning PuGs).
Personally I have raided quite a bit in the past (>200 LIs) as well, but have stopped doing so shortly after wing 5's release.
And thats mainly because the effort-input to reward-output ratio is simply not good enough.
I still run daily T4s. And not because I think they are particularly fun, but because they are an enjoyable gold-farm.
Personally, it comes down to a basic utility function to me.
Therefor, Raids should be dramatically more profitable. The "hardest" content in the game should be the most profitable. Hands down. Even when pugging them.
And that also means they should be more profitable even when you wipe a few times or encounters take longer.
If a player farms 20g/h for 2h a day for a week straight, they make about ~280 gold.
And this might be radical, but personally I think, that raids should award double that. At least 40-50g per raidwing (which is about 1h even when going slow?).
If we are worried about gold inflation because of this, it's always possible to restrict it to some extend.
Like "weekly" achievements (similar to dailies).
Anet could just put 2 HoT + 2 PoF + the latest release in such a rotation.
So we have 5 * 40-50 gold per week. And 200-250g for a 5 hour weekly (or even 7hours when going really slow) investment would certainly get me back to raiding.
(As opposed to the 280 gold for 14 hours of investment).