This isn't gonna hurt the TAMIYA following at all, rest assured. TAMIYA fans are 'loyal' for a lack of a better term. This will just bring 'more mini fans' in general.
As far as a 'controlled chassis'. I like to think of it as the 'limited adjustability' of the M03 is what makes it so appealing. This HPI chassis looks to have that same 'limitied adjustability' aspect to it. I saw the opportunity for competition in the mini class once Tamiya released the M03R (with adjustable camber, roll-center via the new rear uprights, and new front knuckles). That platform threw the whole 'control chassis' rite out the window.
$0.02