Throw in some iteration on both arti perks and aspect perks, remove cross-moon access to perma powers, remove perma monos. With my capture changes below, there won't be any unheld monoliths, so the likelihood that you won't have access to at least t1 is low.
Battles and Monolith Capturing
Unlock one monolith every weekend. Each monolith will have a unique 'battle' or choose from a battle list at random, options including:* Team FFA Team Bloodbath Familiar Battles (pick one, battle til lose, last moon standing wins) Hot/Cold (Shadow lovers?) Gemhunt "Great Hunt" Summon mob hunt Trivia Gambling games where you get booted once you lose X amount of gold at the table.
The winning moon locks the monolith into their possession until the list cycles through again (so ~2 rl months).
Effectively, this makes monolith battles recurring weekend events.
*If you want to be lame and lazy, it could just be PvP arena events in Monolith arenas that pop up a little before it starts, but my idea allows more general participation and we need more familiar battling.
This is basically 'holding' a monolith as now, with a reskin and changing it to the full 5 to the holder, -1 from the other moon, as well as the +1 to your moon sisters. Time to siphon successfully scales down with the number of monos your moon holds. The aggressiveness makes it more sensible as a 'come kill me whenever' action, and it keeps the system from being static outside of the battle windows.
Powers Some are godawful (Res, clearsight), others are lackluster (mimic is okaaay? Terrify is not the worst but there are plenty of fear skills for players and more for mobs), others are awesomely crazy. I'm also not particularly fond of passives for something like Aspects, so lesse what garbage I can come up with.
T1 - Travel skill (Gaze) + add a high-level bashing and questing area on each moon T2 - Failing on this one, so w/e gimme ideas. T3 - Mob-based skill, 1m cooldown on all. AoE terrify (S), AoE peace (A), AoE disruption and amnesia (M) T4 - Movement skills. 2-5m cooldowns on each. Moradeim - Fracture (dir) - Blink in the direction, leaving behind a decoy that fully transfixes the first person to attack it. Sukhder - Impact (dir) - Charge in a direction, breaking through walls and movement blockers and causing AoE fire damage and stun. Aryana - Embolden (target outdoors in area) - After a channel, fly to the target on a beautiful moonbeam and give them a significant health and mana heal and cure 2-3 random afflictions in the process T5 - Epic skill - Warp as is, Inhume nerfed to 2m duration /5m cd, Resurrect buffed to instant use and a 5m cd
Assuming you mean that the combo speed would hit ~2.6s (10-11% + L1 statpack balance) without need for diadem either. I don't really feel like it needs a 0.15s slowdown from where the class is arguably balanced atm, but it also wouldn't be the end of the world for me at 1 lost aff per like 15 seconds.
Diadem still has uses for Assassin even without it being a requirement to hit the real aps.
Linking the arti damage to relapsing is interesting and seems fitting.
Anecdotal note about the issue the buyin presents: Leathon recently switched from Assassin to Defiler despite interest in the class almost entirely because the buyin was off-putting compared to working with another class.
Unrelated Assassigade artifact notes: There is also room for artifacts that don't offer up a straight aps boost but help with playability. The whip is garbage because garrote is garbage. It'd be better off deleted or swapped to something flay/scourge related. I mentioned a faster swift attach arti elsewhere, which would help with flexibility without adding raw aps. Crap like that.