I completely agree with Valv.Piti that this year the number of TTT's is only so high because it's a tdf preparation where the TTT will be crucial. Hopefully the number of TTT's will therefore go down again next year, since while I don't like them in gt's I absolutely hate them in one week races. To see why, look no further than Tirreno Adriatico last week and see who got 2nd. Damiano Caruso only got 13th in the big mtf, finishing last in the group with most gc contenders, was one of the worst gc rider on the murito losing 24 seconds, had a mediocre ITT finishing 37th, but he got 2nd place overall because of a TTT where he wasn't even the reason for the team being so strong. I know many people like to call cycling a team sport, but it isn't. A team sport is a sport where at the end of the competition the official winner is a team, in cycling the official winner is one rider. In the case of Tirreno Adriatico the winner was Kwiatkowski, not sky, while 2nd place was Caruso, not BMC. And since it isn't a team sport I think that there is no way the team of a rider should be the single reason why this rider finishes high in the gc. I mean with TTT's we have reached the point where you can be a bad TT'er but win the race because of TT's. The team's strength may be important but it should never be the most important factor.
The advantage of gt's compared to one week races is that while short stage races like TA often only have one big mountain stage, gt's usually have more than six, so no matter how strong your team is, a guy like Caruso won't finish on the podium without being one of the strongest riders in the rest of the stages. That said, I'm still not a fan of TTT's. Maybe the only reason for that is that we are currently witnessing the sky era. In the op the main argument for TTT's was to reduce the strength of mountain trains, since in theory the most important domestiques in the mountains are bad in TTT's so you have to find a balance in your team between TT'ing and climbing. However unfortunately that's just theory and in fact there are many riders who are good in both and the best teams will be the guys who have these riders in their squad. So if Froome may participate in the tour, and we assume his main rivals are the Movistar guys how would the race unfold: (ofc their are many more rivals but I'm just using this as a simplified example)
Sky has the way better TTT team so they'll gain a lot of time on Movistar. In the mountains the guys who are great TT'ers are also great climbing domestiques so their mountain train can work just as usually and since they already have an advantage they can even use their tactic of controlling perfectly and don't have to use their strength for setting up attacks. Movistar who have lots of great climbers in their team can try to derail the sky train, but unfortunately their climbing squad isn't at full strength since they had to include guys who are good on the flat in their squad to not lose too much time in the TTT.
As you can see, a TTT doesn't only help the strongest teams it also hinders the weaker ones. And if we have seen one thing in the past tours, a strong team already is a huge advantage without a TTT in the route.
As I've written before, if we wouldn't have a dominant team like sky right now my opinion might be different. But after all the organizers don't make their routes without knowing the teams so in my opinion, if you know that there is a dominant sky team right now, why on earth do you deliberately make your race more boring by including a TTT?
Anyway, there is one place where I would theoretically like TTT's which is the WC. The TTT event is usually good to watch however I'm still annoyed they don't have national teams. Isn't it one of the unique things about the WC that you have national teams and riders not competing for who pays them but for their country. If they would make the change to national teams there'd be at least one TTT I absolutely like.