There a lot of folks doing grind to win to use their 1000+ champion points to dominate PVP and trials. New folks, casuals, anyone that doesn't grind is left in the dust, leaving them horribly under leveled. This also affects us in the PVE side where dungeon challenges and achievements are based on they highest speed players, not the average player.

On the other hand, capping or removing champion points removes a lot of work players put into the game. Alienating folks with that much investment risks a mass exodus of the older players that mentor new ones. We want to give folks reasons to improve but not to the point no one can compete with them, that makes things boring

Some inspiring solutions:
You can read more on @Gidorick 's solution here: CP Active Passive Bar & CP Burn Concept which focuses on slotting active passives and burning through CP points.

You can read more on @Rune_Relic 's solution here: CP - Suggested fix and compromise which focuses on locking thinges to a single constellation per tree.

From my own thoughts and the above I've come up with 2 concepts that need a theory crafter to flesh out better.
Concept A - a straight X amount of points that can be spent in competitive situations (pvp or trials). This would be simple and would not preclude folks from grinding. Say for example folks could only spend 300, this could be 300 across all constellations or all into one. However, to put all 300 into the ritual, you'd still need 900 champion points, so still giving reason to have a high pool. This would get some annoyed though that 600 are unused.

Concept B - a Major, Medium, Minor constellation assignment. The assignments would allow a major to take 120+ points, a medium to take 75-30, and a minor to take 10. This would cap the amount of points allowed in a constellation and prevent folks from having infinite resources, high damage boosts, and impossible armor; but still allow powerful builds with proper planning. This also would still give grinders some advantage like above, where major and mediums paired together under the same sign require an over all high amount.this is less simple than concept A, and REALLY needs a theory crafter to look at it for a balanced model

So first off...
The non-vet campaign - we need to drop any champion point bonus. This is a campaign where new folks get used to the game and get their first taste of PVP. There is no reason someone should be getting any veteran bonus in them. I can not see any solution from the varying systems that will work well or not frustrate new players with their lacking power. If we get enough high levels playing down there maybe offer another campaign.

For the Veteran campaigns:
Unrestricted - same as it is now, unlimited CP applies, high level grinders verses high level grinders. Folks know what they are getting into joining here.

High points - using concept A from above, this would be a 1200-900 CP cap campaign (or 2-3 major constellations from concept . This would still be restrictive to some, but would stop the specter of a 3600 CP plater just stomping g through everything

Moderate point - this would be around 900 - 600 CP points with concept A (a few majors and mediums with concept . This should be a spot most folks will be around the start of next year.

Low points - this would be around 600 - 300 CP points from concept A (or just 1 major, medium, & minor with concept . @Gidorick & @Rune_Relic's solutions would be about in this range. This would get folks a foot hold into PVP, but grinders would find less benefit here

No points - just like the non-veteran campaign, new vets have a place to play when they have barely any points. I feel this is an important option to keep.

unrestricted Emperors - adding to these campaign rules and improving the Emperorship, lift CP restrictions when crowned, or at least boost their effects, giving added incentive to the high levels to try for it.

Several concepts need to change with trials as it is. As earlier posts showed, points are only affected by time; not by skill, deaths, or the lower levels. This means the ones that grind the most, not necessarily the most skilled, will win. There are a few ways we can handle this:

CP party max total - where a group is allowed a max number of Champion points to be assigned to be counted as a valid run. This would mean healers or tanks could skirt low on CPS to give them to DPS to make better use. A group could also run with lowbies or without members to secure more champion points to use.

Overflow CP hurts score - give each member a base amount of points, regardless of totals, and each point they assign over that counts as - 5 to score. This doesn't prevent folks from over spending, but hopefully they will be thrifty in their use.

Straight restriction of points - using concept A for about 300 points (or concept B with a major and a few mediums) will keep the trials difficult for the gear it produces. Thus is around where I see @Gidorick & @Rune_Relic 's solutions touching.

I feel that despite most systems we've discussed, let the players use all their champion points in PVE situations. Some one that has managed to grind out however many points has spent a long time invested into this game already. If they are leveling an alt, grinding a piece of gear, or whatever. If they manage to do 40k to a boss while the lowbie can only do 10k, so be it.

Scaling dungeons and PVE content should not be measured by these high CP user. Realisticallyit should be set to be challenging for someone with 90 CPs, and less difficult for ones with 300. After that, just let folks enjoy an easier grind for dungeons and challenges they may have already done 50+ times.