I did a lot of frozen fruit in the beginning of my intro to this lifestyle. Personally I really don't enjoy frozen or cold foods much, but every now and then I enjoy it. Also, if I have no ripe, fresh fruit, I might have one or two frozen meals a day. If I have fresh greens I like to eat them straight. Green smoothies are an occasional thing for me.
Usually my frozen percentage is probably less than 20% a week. I think it is technically okay...but you're not getting the nutrients you could be getting with fresh fruit.
I think its in the 811 diet book, but eating a lot of frozen will harm your beneficial intestinal bacteria (flora) and causes all kind of unbalance. Do some searching on this forum and you will find some more information.
When I have smoothies, I have a banana-frozen strawberry smoothie, with maybe 2-300g of strawberries. So long as you don't overdo it (meaning you don't only eat frozen fruit, which'd be really, really hard anyway), I don't see any problem with it.