One of their problem is that they often have way too less informations. Simply because they don't try to get them.
As CT they're almost always just waiting on the bombspots while knowing nothing about the Ts.
For example some "fakes" of iBP were so obvious. They threw some grenades on both bomspots, but on one bombspot they were only like 2-4 grenades, and then it became quiet. In such situations you sometimes have to take a risk and make some offensive move just to get some infos. For example if one of them had flashed mid, his mate could have taken a short peek at mid and realize that it was actually only 1 guy there and that everyone moved to banana. Knowing this would have helped so much. Knowing when to do things like that (it could also be a trick, "doing something that looks like it's an obvious fake when it's not a fake at all", my favorite thing to troll the enemies) is a very important skill.
And the knowledge of how to use such infos is what separates the good IGL from the bad IGL. The IGL needs to see some patterns in the way the enemy plays (even playing random is a "pattern") but most of all: get a feeling for "how the enemy thinks".
But of course an IGL can only do his job when his mates give him some infos.
This is what made gob b an outstanding iGL. He used his players perfectly to gather infos and he was brilliant in evaluating and using these infos.
And like I said: They should try to get more variety in their playbook. Especially as CT. You barely see them surprising enemies with an unexpected move, they seem to fear that it could go wrong so they stick with their very static, defensive and predictable system.
They are actually very good trained in throwing timed flashes. They should use this to make some unexpected offensive moves from time to time. If you throw a perfect "golden flash" (meaning that one players throws a flash around the corner such that it explodes right when it comes around the corner and the second players move straight out), the risk is quite low but the peek allows you to get some important informations about the enemies or even catch some of them off-guard. Also it forces the enemy to always stay prepared, while this constant defensive CT play of Titans means the Ts have way too much room to move around safely.