I thought the finale was good. It was bittersweet and I love bittersweet endings. If it had ended with a single kiss sparking back all her memories I would have been pissed, but with Chuck's persistence and Serah giving him a fair shot (because she knows they had something, otherwise she wouldn't be where she was and let Chuck kiss her) gives a lot of hope for their future.
As for wanting a hint of memory, I feel like they were hinting at Serah's memory getting recovered during the entire finale. The montage they had with Chuck retelling Serah their story obviously meant more to Serah than it did to us, otherwise she wouldn't be tearing up or laughing while listening. I feel like that was a moment of hope for them both, and the kiss sort of just sealed the deal. Perhaps that was the wrong order to take for Chuck, but I feel like it worked a lot better this way and definitely feels less cheesy. Though it is Chuck, some cheese is perfectly acceptable.
It felt very rushed, and I feel like Chuck getting the intersect back is just how a season finale should be, not really a series finale. I feel like if they planned to continue on Chuck, it would be with Serah's recovering memory rather than a quick fix. But I was surprised and honestly proud of Chuck for not taking the easy, super convenient way out like it does for most situations. The pacing was terrible, but I loved the content of the series and I will be terribly sad to see it go.