The larger drivers on the cf-70s will probably let you crossover your sub a little lower if you want which would reduce potential localization issues. As to whether they will have a fuller sound, its hard to say. The overall timbre of the speaker could change with the larger drivers which will make it sound more full, but it might also increase beaming in the upper midrange. I generally prefer larger towers myself.
Main System: SVS Ultra Towers - 15" custom ported subwoofer - SVS PB-1000 - Yamaha RX-A740 Aventage. 122dB @ 16Hz!!!
Computer System: Carnagie Acoustics CSB-1 - 12' Onkyo sealed subwoofer - Pioneer VSX-92 THX
Other speakers owned or auditioned: Aperion T6 - Ascend CBM-170 - Energy RC-10 - Wharfdale 10.1 - Arx A1b