The 23-year-old played every single minute across the competition and was a try scorer in the 51-3 thrashing of the Scots but missing out on a hat-trick of titles was hard to take for the 34-times capped No8.
"This win is bittersweet, I guess. We're frustrated and we've got regrets about the way we played in Ireland and England," said Faletau.
"Scotland were a bit more vulnerable when they got the red card and we managed to get a few points on the board. We were good in patches but we could have been more clinical, which is something we need to work on.
"Overall, we've got to be disappointed with how the tournament has gone for us. We wanted to win the Championship but it didn't quite happen for us."
Next up for Wales is a summer tour of South Africa, a trip which features two Tests against the Springboks and could possibly include a mid-week game in Port Elizabeth against the Southern Kings.
And, while Faletau was frustrated not to be competing for the 6 Nations crown on the final day of action, he insists the squad will head to the southern hemisphere in decent spirits after racking up seven tries in their last outing of the spring.
"It's not mission impossible in South Africa. We'll be going out there with optimism," added Faletau. "The boys won't be going out there to lose so hopefully it will be a good tour for Wales."
Faletau modestly stated that he would 'probably only give myself a two out of ten' for his performances in the tournament as a whole but that opinion wasn't backed up by Wales forwards coach Robin McBryde.
The former Test hooker was delighted with the manner in which the Newport Gwent Dragons star stepped up repeatedly across rounds one to five and he is predicting even bigger things for the youngster in South Africa and beyond.
"Toby's been our most consistent player throughout the Championship from a forwards' point of view," said McBryde.
"He's delivered fantastic performances, he's never injured, does all the training sessions and just gets on with his job. He's got the potential to get even better as well."