I think the argument here isn't working because we're coming across two different ideas of when matches ending in time-outs actually mean. People either believe that running the clock is an actual strategy that should be an influence in matches or believe that all characters should have more than enough time to effectively rack up damage safely and have enough time to successfully land a kill. One good example I think would be Wario vs. Falco.
When Wario gets a lead stock on Falco, his defensive game makes it extremely difficult for falco to manage a kill move. Should Wario keep this advantage just because we have a timer that makes this possible? 8 Minutes isn't really enough for Falco to safely rack up damage and get a kill where as 10 minutes would be a lot better for Falco. I believe that just this 2 minute change could change the match up ratio between these two characters.
I think that this all just breaks down to if people believe that the clock's reasonable yet abusable time limit should be allowed to influence a win (assuming that no one is just planking or stalling...cough mk...). Some people believe that matches should be played as if there were no clock, while others believe that having a clock builds strategy and makes matches have more competitive options.
Personally I believe that if a character cannot win a match in 8 minutes consistently (like diddy), it is all apart of the match. I enjoy having the clock influence the match and force a conclusion within reasonable time constrictions, while allowing options that can add more ways to win a match (as long as it isn't just stalling or planking). To me the clock brings a sort of balance and pressure that makes matches more enjoyable, knowing that the mindsets of the players are always racing and trying to perform accurately within a timely fashion. This reminds me of chess matches that are either free time or have a turn clock. Both have different affects to an outcome winning player, while both are still competitive and used in tournaments.
Maybe the answer is to have the time (being either 8 or 10) as apart of the counter-pick process. This could allow the best of both worlds to the table. Of course, like anything, this would require a lot of testing.
In a world where we can only have 8 minute clocks or 10 minute clocks, personally I enjoy the 8 minute clock since it fuels excitement in the matches to me, like running a timed mile.