Oh boy, this again. I actually did sit there and timed from the results screen starting to the next stage loading (did not count the training stage since the WiiU version will not have this) of both pools and bracket matches in the Invitational listed in Thinkaman's topic. Guess what? While the first intermission was ever so slightly longer between matches from what I saw, none of the 7 matches I looked at (do your own dirty work if you want a larger sample size) had any downtime over a minute except GF which had one instance of > 1 minute between matches within a set due to, get this, them wanting to change stuff on the stream. Nothing to do with the players. In fact, the range I saw was between 22-43 seconds. Unlike you, I did not pull a number out of my ***. This number will ever so slightly raise when the WiiU gets a full stage striking list + custom controls + ban, but that affects both sets in equal time lost (before game 1 and after game 1).
We'll take a safe estimate of 40 seconds between matches (the results screen being roughly 7 seconds of this). In a 2/3 you see roughly 1:00 per set of downtime. Anywhere from 40 seconds to 1:20. In a Bo5 the range is 1:20 - 2:40. Difference added is 1 minute. In a 64 man bracket with 8 setups you can optimally have 18 rounds of play in a double elim bracket unless I stupidly counted wrong.
Now the issue here is thus:This is theory in a vacuum (also 8 setups is pathetic for 64 man) However, even if the average time between matches was doubled, that's still less than an hour added. I really, really implore you to look at actual data for yourself by watching tournament sets. Pre-game and post first game are the longest gaps in a tournament set. Period. Very, very few sets will last for more than a minute between matches in any Smash title and if they do it's stream shenanigans or other horrible things like rulesets allowing for coaching.
Even the Japanese matches, eh? Even with loading issues it takes less than a minute.