<off-topic> I don't think this entire community is devoted to bashing xcom2012. Yes, it's different, but it does have a lot of interesting ideas. On the other hand, I can see a relevant percentage of this community agreeing that it's nice to use moderate language and abstain from trying to bully people into accepting your beliefs.</off-topic>
the circle graphic, while simple and nice-looking, might lead people to believe that something will be affected which in truth isn't, as well as vice versa. A highly-precise tile-by-tile recoloring, while correct, will probably be ugly. I really don't know what would be better. Perhaps you could provide both? Like the path preview option, which can be toggled between "off", "arrows" and "arrows w/TU", this could be toggled between "off", "circle" and "tile-by-tile". People could then decide which it is they like best.
The idea of units inside the blast radius flashing as a visual cue is certainly a nice extra, if it's possible.