Not remotely, IMHO ... you can never judge any team's entire season by one game, and we have completely dominated Miami this year. Guess it's a half-full half-empty kind of thing, and I like to judge a team's season by it's entirety.
Some would say last year was a failure, and it was in terms of not acquiring the championship, (which is the ultimate goal), but it was also a very successful regular season, and an incredibly resilient post-season, coming up only a few points away from the trophy.
I don't think you can look at this the same way, though, because our regular season is already successful, despite what happens Sunday ... 2nd seed or 3rd, the majority of other NBA teams would consider as a successful regular season.
But to say a whole season is a failure, (or not a success) because of one game? That makes very little sense to me, statistically or practically, and while seeding can certainly help, it is far from the deciding factor when it comes to the playoffs, (even in college as we've seen this year, and there is much more quality inbalance between teams in the NCAA).
(Not to mention what we've accomplished with the incredible amount of injuries and drama we've had to endure).