I must admit I didn't notice any frame drops on my original PS4 compared to the Pro (played back to back).
Really enjoyed the mission and strike. At the moment it feels like they have taken everything that was good about D1 and amped it up (which is what I was expecting tbh).
The strike in particular was a stand out for me. Plenty of verticality and space to try different approaches for each section. The triple stage final boss felt good and had the right level of challenge (difficulty wise it felt like earlier strikes in D1 when initially levelling).
If the rest of the missions, strikes and patrol regions are up to the same level/quality then there should be a decent amount to do and (ultimately) replay.
First impressions are that the Crucible felt, well, like the Crucible (at least in the control mode) but with a longer TTK. The map chosen was find for 4v4 but I will withhold judgement (on 4v4 vs 6v6) until testing the other maps.
Balance felt fine with the limited weapons on offer but the Hunter/Warlock auto (the one that looks like a AK74u) did feel better than the others. Sub classes all felt decent enough (I do love the hunter dodge + auto reload*) but I haven't played the Warlock/Titan enough (in PvP) to really get a feel for the specifics.
Overall first impressions are positive.
*Although this does seem somewhat weak compared to both the Warlock and Titan perks.