A lot of companies jumped on the cheap cash-in bandwagon. It's how the gaming markets on iOS and Android operate. Most third-party Wii titles were shovelware. There were a few diamonds in the rough, but they were generally the exception and not the rule.
Sega has made a lot of crap over the past few years, most of it Sonic. I think Secret Rings was actually better-reviewed than the 360/PS3 game that came out at the same time. They also tried to take a ride on the licensing merry-go-round and they put out a lot of crap licenses, though Gearbox did them kind of dirty with Aliens. But you could chalk that up to Sega not exercising proper oversight.
Sega's also made or overseen a lot of really good games on the 7th gen consoles. I enjoyed every one of Platinum Games' Sega-published offerings, including Madworld on Wii and Infinite Space on DS, and indeed they were some of my favorite games of the generation. Valkyria Chronicles was my favorite game of the entire 7th gen, VCII was probably my favorite PSP game. The only game which came close to it was Ni no Kuni. I've also enjoyed Yakuza and am happy that Sega is continuing to release the series over here despite very niche-y sales. Honestly, I've enjoyed some of their offerings as a third party more than I did their offerings on their own consoles. It's too bad they haven't done better as a third party, and it's kind of too bad they had to let 2K Games go.
They have talented designers and some screwy managers. Doesn't help that the Sammy half of the company was more interested in using Sega characters in pachislot games than in video games, and Sega's customer surveys still kind of try to steer you towards their mobile offerings.