Disagree. Switching apps is not instantaneous. The multitasking button doesn't bring up the panes fast enough. Google Voice, in particular, is very laggy for me. Sending a text then moving back to the inbox can lag. Things like scrolling are for sure much nicer. But it's not at all fast enough for me.
Part of that is possibly hardware. Task Switching does have a small delay between pressing the button and the display firing. It's really quite small though. On the Transformer Prime it's near to instantaneous. Can't talk about Google voice as I don't use it and I've never noticed the text thing.
Bboy your curse is that you demand perfection. At first you'll think the newest thing is perfection, then after a few days, maybe weeks you'll start to focus on the areas that could be a tiny bit better. Before long this focus becomes all consuming. Until the next phone comes out and so the cycle repeats. I think the issues is that this focus can lead you to exaggerate. Calling the Galaxy Nexus 'laggy' is a gross overstatement. There my be small parts which could be tightened but the overall experience is one of the fastest, if not the fastest smartphones on the market. Only the iPhone 4s and the HTC One X can hold a candle to it. A bit of perspective from somebody who sells Galaxy Ace's all day and truly knows the meaning of laggy
Obviously with the next Nexus and next software revision Android will become more responsive, smoother and faster as it has with every update. But as progress marches on and perfection reaches new heights you will never be sated. It's like that temple run score that you know can be beaten. It's an amazing score, you pat yourself on the back for doing it - then one of your friends bests you by a couple of thousand. There will always be a higher score. There will always be a fly in the ointment to prevent perfection.
I've forgotten my point! Ahhh, that was it - Perspective and a little dose of realism!