He did better than Lloris, who cost Spurs a few goals and some nearly goals last season with his over-eagerness to rush out and sweep. Unfortunately for him, he didn't always make the right decisions on when to come out for it. Also, if you're pointing out De Gea's howler against Sunderland, how can you then list Howard, who had some tasty howlers himself last season against Chelsea and City? In fact, he was absolutely shit against City when we needed Everton to get a result to help our title hopes.
Yeah, this is the thing, you really shouldn't look at a howler or 2 and let that scew your whole judgement on a player and let the 35/40 other games he played well in count for nothing, Gerrards performance last season is a good example, if he didn't slip and we won the league i'd bet a fair few fans who are all a bit meh about his performances last season would have been looking back with a way more positive slant on him, same with Kolo, honestly thought he done a sound enough job overall for us last season but those 2 massive howlers just completely override any of the good he has done in a lot of minds, even now if you ask another opposing fan about him near on every single one of them would lol and say he is a shit clown, all based on those 2 mistakes.
Same goes for a player hitting a purple patch, remember Amir Zaki? i fell for that one, thought we were seeing some great striker making his mark lol, even Giroud looked the nuts at the start of last season, it is hard not to be influenced by short term form or certain high profile incidents with players, that's why i don't think its the wisest move to write van Persie off after a stop start season under Moyes where he was clearly unhappy but still managed a 1 in 2 record in the PL.
Btw im very likely being hypocritical bastard on some of this, lol, it really is hard not to be heavily influenced by the short term or certain big incidents when sometimes you should hold your horses look at the bigger picture.