Visuals are the first big change you notice in PvZ 2. But this is the way the App Store works these days. I'd much rather pay US$10 or $20 for a full app than constantly be treated as a mark.
If Candy Crush is the great Satan of IAP abuse, PvZ 2 is certainly an acolyte. Instead, the emphasis has transferred to in-app purchases, with hardcore upsells throughout the app. There are bits about it I'm disappointed with, but overall, it has charmed me. On it is Plants vs Zombies 2 (free, or more realistically, 'free, but you are an IAP target waiting to be plucked repeatedly'), just released last night and since about 11PM yesterday, well, let's just say sleep and work went by the wayside.