I believe if you're already 30 you can't use the boost? I had a friend try that over the weekend it wouldn't let him, but you can use it on a character under 30, as the boost gets you to 30 gs500 and completed story, which you need to advance to ny.
My skill builds were mega fucked, skill cooldowns were fucked, my turret use to be 21s cooldown with my hardwire build then it became 16s, my seekers were around 16s cooldown became 30s cooldowns and 100k less damage, mods super randomly fucked. Btsu gloves got fucked and usable only for hive now, the blow up on deployment talent on it got moved to chest talents. The up side is with the skill tiers it also gives bonuses to skills for all the levels, so a lot less reliance on mods.
I had 300 gear stored and dumped everything into the recal library and managed to get a lot of max rolls to fix up the build a little. Went out to do a bounty and damage felt weaker, but with that same build starting in ny it felt the same as old, so I would say starting in ny at 30 the mobs felt like they're almost wt4. I hit 40 last night(I actually hit 38 clearing just two of the zones) and finished the campaign which unlocks the new shd level progression.
The new world tiers are labelled the same as missions normal to heroic(you can choose whichever you want), and probably does use the shd levels as a measure(in the end it looks like 10% boost to that stat area). I fired up challenging level with my half asses purple/gold gear and it was challenging to kill and survive in a cp3, while on challenging in dc before I would one shot everything with the seekers.
Edit: Just saw a vid with someone with hardwire build with 1million armor and shield with 7million hitpoints, stuff will get easier with proper builds.
Now to see if I can put together a decent seeker build using either brands or hardwire.
So I got to 40 this morning and playing basically all day and it seems like they have you doing the same shit you were doing a year ago, lol. same loop but now even more confusing because there is no gear score to judge which difficulty you should be. I did some normal, I did some hard. Even tried 2 bounties in challenging which were umm, challenging to put it lightly lol, total bullet sponge hell, and they even heal if you leave them alone for too long. Still doable but crazy. Also, no new strongholds either in NY. Hopefully they add some.
I'm honestly surprised you got the expansion considering the amount of shit you give the game.
No strongholds but the seasonal play is what is going to carry the game forward using the theme of the expansion as a base, if you finished the campaign you know what I mean, talk to the season vendor and it shows you what you will be doing for the season in the next 12 weeks. You can still go back to dc and do the usual stuff as well at 40, invaded, strongholds, raids, etc.