1st Round best of 5 is the most important thing. Of course it's not gonna happen but the argument for is everyone loves a David trumping Goliath story. Next, I would go with going back to the 4 divisions (2 in each conference 1 & 2 seed) everything else a free-for-all, like other posters mentioned.
The top 16 doesn't change the problem. Y'all are only thinking the Top 16 teams based on everything else remaining as is. You would do away with conferences and divisions, so you have to balance the scheduling. It's the most logical step. It would still produce the same amount of 35-41 win teams trying to make it into the playoffs.
They could do top 8 in each conference, regardless of winning division but then you don't reward the division winner, which every sport does. Okay, here's my listing:
1. 1st Round Best of 5
2. Finals 2-2-1-1-1
3. Conf Semis & Finals 2-3-2 - Get these ishes over ASAP for boring series. If you steal one, you have potential to win in 5. Home court holds, takes it to 7. Leaves room for potential upset and rids of unnecessary games.
4. East vs West, 4 Divisions, #1 guaranteed home court, #2 guaranteed spot, seeding based on record. They can do this with the 6 divisions but I wouldn't have #3 a guaranteed spot. I guess you sort of have to though...but that's why you only have 2.
5. Televise the actual ping pongs. No more of that closed "secret" envelop ish.
6. As for the lottery - EVERY team has a shot at #1 breakdown as (worst-best record order)
Bad Teams 1-6 = 6% chance at #1 (36%), 7-10 = 5% (20%), 11-14 = 3% (12%), Playoff Teams 15-30 = 2% chance at #1 Pick (32%). Helps some of the middle-of-the-pack teams out. Discourage tanking. Of course the trades and conditional ish remains.