Please add traps to ALL dungeons, singular or roulette.

[Acidblood]

... It's too late to restructure the designs but something to break up the monotony would be refreshing... Dungeons play a big role in that and our list just keeps growing

I'd take these as the two key points, in that they really need to come up with ways of utilitising the dozens of existing dungeons, primals, etc. that we already have, but that see very little use outside of over-geared XP or glamour runs.

Two ideas would be:
Min iLvl roulette - similar rewards to 'expert', but can be any dungeon at min iLvl.
Min iLvl challenge - 10 dungeons and 2 normal trials are picked per month, clearing each at min iLvl gives tomestones, clearing all gives a piece of gear.

A bit more complicated, but an idea for old raids and ex-primals (outside of a roulette) could be:
Help a newbie - Twice per week, clearing any of the old raids or ex-primals, while synced, with a new player, gives an extra bonus for all players. The more new players the bigger the bonus.

[TaleraRistain]

No way. People run right over these even when they're big and glowing on the floor in PotD. I can only imagine the wipefests if they remained hidden.