So you save 108 points and get a bunch of extras but lose 3CP (which, to be fair, would've been gone to the relics anyway). Seems fair to me. Now if their loadouts were just better.
I really think it comes down to how much you want to play a bunch of monat crisis suits running around doing stuff. That style is no longer possible in 8th except by taking The Eight.
If you want to play a more conventional T'au army with massed broadsides/riptides then they are going to look awful to you!
So as for the points costs I worked out that if you think the drones along with Farsight, O'Vesa and Ob'lotai are legit at normal cost then the whole set of commanders cost 395 points between them. So really you are looking at paying points as if they were regular crisis monats with a bit of a points premium for the character keyword and the commander statline - viewed as slightly expensive crisis monats I think their loadouts look a lot better. A lot of the reaction, including my initial reaction until I did some more analysis, was coloured by thinking of them as commanders which are a premium model in short supply and which therefore we would never use such weak and wasteful loadouts on.
For 395 points you get offensive capability of ;
3 plasma rifles
2 fusion blasters (fusion blades)
That all comes with BS 2+ and WS 3+ so its actual output is a lot better than it would be on equivalent Crisis Suits, not quite twice as good but nearly so when we allow for prevalent -1 to hit penalties in the game.
Defensively they all have character keyword and there are 26 wounds mostly with T5/3+ but with some 4++ and of course one model with 2+/4++.
If they all had optimal weapon loads then this would be broken as heck, even if we had no points discount it would still be a return to Commander Spam which was justifiably hated by all non-Tau players. I think GW erred on the side of caution with this, they know the weapon mix is going to be hard to make much use of and some of the support system choices are poor (I am looking at you Brightsword) so they gave the whole thing a points discount. Personally I would rather take on the challenge of a difficult to play unit that is widely regarded as just for fluff - if I do win with it I will feel like I really earned the win and nobody is going to flip the tables like they would if I just brought a Ta'unar.
 Ob'lotai is a steal. Really a bargain when you consider how valuable the Character keyword is on a Broadside; if nothing else consider how many shield drones you do not need because nobody can shoot at it. Add in that it reduces all damage by 1 to a minimum of 1 as well and you have a very tanky Broadside who will keep firing all the missiles all game unless your opponent is determined and resourceful in stopping it.