Generally agree with a lot of Hjarki said, but I have some further input:
Re: rains, I agree that ice storm and blizzard are monstrously good, especially with tar patch and scourge, however there is definitely something to be said for fireballs speed. The rain summoning animations are a bit of a chore, but i personally don't mind the trade off.
Re: procs in BIB, I've tried proccing it up (and alternatively FR) and found that at 50 neither was worth it. Slotting 3 procs means that you're otherwise compromising your stats in that power, almost writing off the power for set bonuses (unless you only want the 3 slot recharge bonus in Scourging Blast). I also feel like I need at least some recharge slotted into BIB to make a consistent attack chain, which lowers the proc chance. I might play with it a bit and move my SB set around to see if its worth it, but I dont think that the damage ends up being that much better, especially since proc damage doesn't benefit from soul drain.
Re: tar patch, totally with you, its awesome. just wish the animation was quicker.
Re: BFR, I would have previously agreed with you, but the animation is absolutely worth it after the late buffs. Despite its long animation, its the best DPA in the set outside blizzard (check the in game stats). Also taking char means not taking Soul drain, which is a game breaker. Perma soul drain is game changing amounts of damage and, in my opinion, invalidates any other epic pool choices. Also, bonus points to BFR (and FR) for being able to slot 4 Basilisks Gaze for the 7.5% recharge + 2 lvl50(+3) damage IOs to optimize damage, hold, recharge, acc and end redux.