I could live without random rolls but if they bring it back I'd prefer they streamline the amount of possible options available so the god roll grind isn't so tedious.
Exotic engram drops DO need to be lessened. The drop rate now is MUCH higher than it ever was under the Three of Coins system back in D1 and that is a contributing factor to making exotic gear feel less interesting (the other factor is the watering down of exotic perks, Peacekeepers as an example: I can... passively reload SMGs while wearing this! WOOO, I guess?).
Clan rewards NEED to go. It was a dumbass idea to begin with and anyone who played WoW back when Blizzard put in guild rewards saw this coming a mile away. Back when Blizzard put it in WoW, it led to mega guilds, people wouldn't consider joining guilds unless they were max level or had specific rewards, or only wanted guilds with specific guild wide achievements unlocked for specific reward items. That's already happening with D2 and a quick glance at the official D2 Clan Recruitment illustrates this perfectly: People looking for clans but only wanting higher leveled clans with 3/4 or 4/4 weekly engram completions and clan recruitment posts highlighting their level and weekly rewards rather than their goals or activity types.
It's a silly idea to give people rewards for an activity they might not even play that week and inevitably turns into a small group of clanmates carrying everyone else for free loot. Erstwhile, the tiered clan perks puts smaller, newer clans at a significant disadvantage to recruiting new players who now expect to be rewarded for clan participation. Blizzard realized this system was bad and opted to gut it entirely a couple years after initially putting it in. Bungie will eventually come to the same conclusion.
Edit: I'll join in on the raid power rankings for the hell of it:
1. KF
2. WOTM
3. VOG
4. Crota
5. Leviathan
Strongly disagree with the exotic engram rate comment. As you allude to in the second part of that, the problem is Bungie made shit exotics, not that you can get them without grinding for years. No amount of drop rate tweaks will make the Tricksleeves not absolute dogshit.
You're 100% right on the clan thing. It's another example of Bungie designing something in bizarro-world and having next to no idea how actual human beings function. All of its problems are immediately apparent. The severe penalities for small clans are just the cherry on top.