I would like to point out that Coto actually said the finale wasn't going to involve time travel BEFORE it was officially announced that Enterprise was being cancelled at the end of this season. Now, whether it was known at the time of the statement that it was going to be canceled or not is entirely speculative, but I think that we may need to consider that that statement was for a Season Finale, rather than a Series Finale.
All I'm saying, is dont be surprised if the Finale does indeed involve Time Travel, especially with the casting of Frakes and Sirtis for said Finale.
Interestingly enough, The Best of Both Worlds was orignally written to be the Series Finale of The Next Generation, but a resurgence of ratings and a Original Series-esque mail campaign convinced them to change it to a Season finale, and now...we are at the same cross roads again. Now, will history repeat itself? Not bloody likely, and it stands about a snow balls chance in Arizona to stay with UPN. The only chance I see for Enterprise to get a fifth season, is either on the Sci-Fi Channel, NBC (which originally wanted to buy Enterprise from UPN) or UPN's mainstream partner: CBS.