Let's not forget that a lot of Swarm's cost is the land claiming that was required to actually build it...
Comparing costs with American rides is also tricky, since they have a manufacturing plant over there, and even with the one in Europe, UK parks still have to pay for shipping...
Would a hyper garner international attention? It's arguable, as a lot of Americans didn't agree with Shambhala appearing in the Mitch Hawker poll so highly as it did, and whilst the Intamin rides are highly rated by several, they're not THAT good... They are very hit and miss rides and certainly won't fulfil the desire for a new intense coaster that Swarm didn't acheive...
Besides, if they really want airtime in a tight compact layout, all they need is Piraten... So it doesn't even need to breach the ceiling of the park... However personal preference would go towards a B&M hyper, but consider a Mega-Lite has 1.2m restriction, then it's a clear choice tbh...