** First of all this isn't a hate topic. Meaning just because you don't like it does not mean it needs hiatus. This means a series that has been stagnated or is just too much in the last few years. With that said let's start.
Sonic
Now Sonic Colors & Sonic Generations are great games. The best 3D sonics for sure. Here is the thing they did 2 great retail releases and Sonic Generations is the perfect stamp esp the ending to let Sonic take a few year break. I'm not talking games like Sega racing. Just the main series. (oh and can the Sonic Riders as they are shovelware) I think 2012 was the first time in years we did not have a retail release. Maybe SEGA is taking a small break?
Final Fantasy
It's fair to say ever since FFXIII it has divided fans. Some like it some hate it. XII-2 divided fans more. The series to put it nicely has taken an interesting spin. Maybe not the good kind of interesting. Square while it maybe getting the sales yet other smaller developers are innovating the genre of the JRPG. Note Xenoblade & The Last Story. Now with Square announcing a 3rd XIII game one that has cause another internet uproar. It's safe to say Square does not really know what to do with the series anymore. Many want Vs XIII and it's been rumored it has been delayed til next gen as Final Fantasy XV. Some think it's vaporware. However this is the game most want yet Square seems unwilling to deliver. If they can't deliver what fans want then maybe the series needs to take a long break.