Last night it's Season 4 Premiere saw a drop in ratings compared to it's season 3 opening episode. About a 23% drop.
So did Supergirl.
Seems your not the only one losing their excitement over this stuff. The Flash is barely fun to watch anymore. The Showrunners have really screwed this show up.
Oh, and Barry can already travel in time on his own and travel to other dimensions on his own too (at least, under special circumstances he's done it on his own). So, no, that's not going to be a new power because, technically, he already has it.
Barry's time/dimension travel power has worked with assistance of tachyon boosters or RF or Kid Flash or Supergirl giving him a speed boost to open the rift.
Now he is charged up after being in the SF for 6 months so his powers are likely at their peak. Now he just needs to learn to use them.