Well, i love that the whole crit thing has been sorted, made a few gear choices easier for me :D! the thing i'd love to see now for locust swarm is a higher base dmg, similar to the buff they made to fire bats (maybe not the same number but a similar buff in dmg) so the skill is actually viable on higher MP without having super insane gear and MUST crit in order to even touch the mobs (im talking stuff like mp6-8 here)... Also, having attack speed maybe increase amount of ticks or increase the duration would be awesome, but i think that might be a bit more complicated to implement.
Also, as a note to the actual builds with locust swarm, im running a locust swarm/ Plague bats build... with WIdow makers for mana regen.
Basicly use locust swarm/Widow makers for the trash (i barely even use widowmakers on trash) and for elites, put up locusts and just spam Plague bats for 2 seconds, they die extremely fast and fits well into the whole "dotting" build... i don't know if plaguebats are the best to use in patch 1.0.8 when the mana thingy is changed, on mp2 right now i only click it to hit the elites once and then stop channeling and the new changes favor continuous channeling... but maybe i'd be able to knock up the MP a notch a two then :D!
Also, in my "normal" gear when running 270k+ dps i tried out plague bats on PTR, they are extremely good at downing elite packs, especially those that you can't stand still for all the time...Combine locust swarm for aggro, Plague bats for high dmg dotting and use horrify to fear the targets already dotted you can make it on mp7-9 without insane amounts of EHP :D!
I've submitted for a buff of Locust Swarm, but seeing as the patch might come out soon (rumors are that it'll be released tonight?) I doubt we'll see a buff soon. I haven't tried Plague Bats yet, but I've been planning to try it out when 1.0.8 is launched.
I've seen PTR vids of Cloud of Bats and it seems extremely viable on MP10. Prices of minus reduction cost of Fire Bats have skyrocketed in the last few week, so I'm not really gonna bother changing around to that. (it's a whole different topic anyways!)
to be honest, with some decent mana regen gear you don't need to use "reduce cost of firebats by x mana" items... i have none of those items and on the PTR i managed to kill around just fine on mp8 with cloud and plague bats... remember with the dmg being so insane high on it, it's just a matter of stacking a bunch of mobs and channel for like 3-4 seconds (depending on DPS ofc), so thats like 230 mana (or something like that?) for the initial cast and 66 mana pr. second for 4 seconds, making it 494 mana for a 4 second channel (trust me, 4 seconds is actually alot if you just time your bats)... and if you have blood ritual it's even less and we haven't even counted in the mana regen for those 4 seconds.. not to mention you prolly have like 900-1000 mana, so 4 second channel without any regen or blood ritual will only spend like half your mana pool...
The 4 second channel is mostly for Plaguebats though as they leave a dot that hits like a truck, so you don't have to channel for that long, the firebats im not sure... i did a few mp8 runs (i don't like mp10, even with insane gear it feels so slow to kill things compared to mp8) and i managed to kill most things within 5 seconds....
The relevance this has to this topic is ofc. the use of locust swarm! the aggro mechanics in diablo works in a wonderful way, so when you for example dmg a mob and run, they are gonna keep chasing you (until you at some point outrun them, but you will turn around and dps them again ofc.), and Locust swarm is perfect for just aggroing in the mobs from for example other close by rooms or just packs, meaning you can stand still and channel bats while the locust swarm attracts all nearby mobs to you :D!
Agreed, once more! I don't really see the use of the minus mana reduction cost of bats myself as well because the reduction isn't that impressive to begin with, so I don't think it's really mandatory, neccesarily.
On the point of LS aggro: hell yes! That's why it's so cool. I've already seen a video of some guy using Cloud of Bats with LS with the exact same idea as you just posted.