I would like to have the option of a shared data plan, both for my wife, and for kids. The other option, would be a shared data plan for my iPhone + iPad combination. I'd rather only have one bill, and have the option to carry and use my iPad on LTE without hassles.
Another idea is to have a "small" roaming allowance for the USA only, on a monthly basis. This would be really modest, so for example 20 minutes of airtime per month (it would be nice if it could be banked), plus 50 text messages per month (also with the option to bank them).
Of course the best idea is to allow roll-over of data caps, so for example if I don't use my 2GB in one month, but I use 2.5GB in another, I should be able to apply what I haven't used up in my previous month as credit going forward. I have already paid for the 2GB data plan anyway, so this would make sense.
In general, Telus could learn a lot from T-Mobile in the USA; they've got a lot of novel ideas, and they're totally keeping AT&T and Verizon on their toes.