Whats the problem with BIG? They are a bunch of very good players, but they have not found their breakthrough so far.
Its really a phenomenon:
We almost never see two people showing up, its almost everytime a one man show for BIG.
tabseN is a very good player with excellent aim. CPH Games was not a good event for him, but on BIGs last map he drops 30 frags while all other players were below 10 most of the time (although seeing tabseN dropping a 30+ isn't that rare). tabseN has proven he can show up against top teams too: e.g. against astralis he dropped a 40-bomb on cache (when gob, legija and him still were in NRG)
For me, tabseN is the most consistent player of BIG.
nex has crisp clean aim. yet he fails to show it most of the time. nex easily has the highest skill-ceiling in BIG but it's pretty rare that we see the beast (although it's getting better, he shows up more and more). I think playing with gob b is good for him.
keev has a "yolo"-awping style. he's not really predictable as he's very aggressive with the awp. That'S good for a lot of frags (and a lot of highlight clips :P) I love his playstyle, but he's missing a lot of important shots lately. When on point though, i'd say he could compete with top10 awpers.
legija probably gets the most shit from the community. But he's a pretty good support player. As support player, you have a really ungrateful job and everybody just sees you're not topfragging blah blah, but legijas job is not to frag heavy - its to support, and he does it very well - also he never misses an important frag and he's a pretty reliable second awp at times.
last but not least we got the mastermind gob b. he's pretty experienced and to be fair, he's calling the shots pretty well most of the time. BIG was the first team in a long time where i've seen players block smokegrenades to create gaps or doing that silent jump, you haven't even seen that in tier1 for a long time. Only problem i see with the calling is that BIG is pretty predictable at times, maybe they have to work on being a bit more dynamic.
TLDR: nex and keev have to become more consistent. tabsen is pretty reliable i'd say. legija does his job well too. gob should call a bit more dynamic. If everybody happens to be on point, BIG could easily be a T1 team that i could actually see making the playoffs of a major (maybe not the semi/finals though, thats a bit too early).
I'm a huge BIG fan (seeing they really work hard for their success) and that's of course all my own opinion here, feel free to disagree and discuss with me.