You've to remember this is shared with Toyota and also with Scion in the USA. The US can basically get 3 badges on this car and depending on the badge, they've 1 - 3 specs to choose from.
As it was shared ideas, I reckon all 3 aren't losing much at all really but not doing themselves any favours. I dunno what Scion's rep is over in the states but come on, Subaru's reputation is not making floaty RWD cars that cost a bomb. It's a manufacturer with a pedigree breed and history to boot with that sweet burbble and their immensce turbo charged AWD set ups. Toyota's rep is reliability for they everyday man, but hang on, they've put one of those Subaru engines in it that always blows up.
Straight away both manufactures have lost what'd be loyal customers who've bought from them over the years because they've changed their values. As said, lads will buy a hatch that is 2 or 3 years older than the BRZ before they touch it. The new MX5 is only €32,000. Already the GT86 is anything from €37,000 - €41,000. Toyota easily have more customers in Ireland than Subaru, so there's not a lot of people going to be saying "Ah, I'll wait for the Subaru version." At these prices even Toyota will struggle to sell so Subaru coming in an awful lot later are fecked basically and tbh are probably wasting their time even considering bringer that car near our shores.
As for power, toyota aren't too bad with Variable Valve Timing but Subaru is renowned for Turbo charging. But they needed the flat 4 setup for the feel of the car. Even if you take a Honda S2000. You've a redline of 9,000 RPM and with just modifying the air intake and having a straight through exhaust, the F20 engine can see 250 - 260 bhp.
On paper it's not only the BRZ that looks set up to fail, but the GT86 aswell.