Haha, well 29 isn't "over the hill" by NHL standards; in fact, many people consider that age to be prime. By 26 you're just getting into your first good contract, and by 29 you should be an established player with a club with a decent track record (you, not the club) and ready for the big, "set me for life" contract. Weiss has been with the Panthers his entire career and puts up pretty good numbers; he's comparable to Filppula in that regard, but more consistent and averages around 53% on faceoffs, of which he's averaged around 1300 the past 4 or 5 years.
You're also calling for a "rebuild," and I don't think that's going to happen anytime soon. In fact, I'd bet on a coaching change before a team blow-up.
Statistics tell a different story. Players peak point production generally happens between their 3rd and 5th season in the league, with a correlation to the age they first played a full NHL season. Going in the favor of Weiss is that he broke in to the league before he was 20, so his peak should have come later and his career will last longer, on average, versus players who break in while older.
Still, he has now been a pro for 10 years, and if we are to assume his career resembles something close to normal, is in decline.
http://hockeyanalytics.com/Research_files/CareerCurve-Krzywicki.pdf
The contract situation may be as you describe it, but a player's production is something different. By 26 the majority of players have already peaked, and by 29 they are in noticeable decline. There are of course exceptions, but that's taking on risk. I would rather go for a younger player than one who will be 30 and doesn't have a great history of production anyway (a pair of 60 point seasons and a single 50 point one).
As far as the rebuild, I'm not calling for it. I recognize that it has arrived. This team is awful by our standards, as I keep saying it is the worst the Wings have been in 20 years. Major changes are already happening... you have no choice when the likes of Lidstrom, Rafalski and Stuart all leave practically at the same time. Next up is Datsyuk, in all likelihood. That's a rebuild, folks. We are going to stink it up for a bit, and the longer it takes Holland to realize and react, the further we will fall.