Past Weapon 52 it's only like 8k Hitpoints(!) per Rank as a Tank with 980 GS.
You mean ATV? It's only slightly better then regular ones on casters, on most "physical" DPS the Epic one is even better.3. Boost drop chance of trinket. That is also huge dps.
Most likely, but i won't expect more then a 3-5% Nerfs, which is still huge on for Argus, but not as huge as many may think.4. One "usual" HP nerf to the end boss.