The new model is a great bike and Triumph did great things to make it more appealing and accessible across a broader audience, thus the difference in crowd. The commercial success of the bike is in everyone's best interest.
For the Euros who actually have the sizes enforced, you sadly don't have much choice.
I was unaware the new bike can't fit the 55 profile without some mods, bummer.
People will run what they think is best, I don't care if people run even Shinkos anymore, their bike their choice.
I've run all available 240/5XR16s, these are my experiences, I'm particularly picky about tires and their "on limits" manners. They all work perfectly fine at roughly double posted speed limits and under in corners.
Emax:
The Exedra Max R has every bit of corner grip, drive off corner grip, hole shot grip and better wet/cold grip than the Avon at 35-40% of the price and gets more miles. The extra height is pure benefit. The Emax has without question, the smoothest break away and regrip manners of all 240s, it also has the hardest carcass and gives the least feedback. It has the most hemispherical profile and gives a very linear tip in / adjustment behavior. All of the fastest mountain/canyon riders I've seen on Rockets run this tire. I've repeatedly datalogged sub 2.8 second 0-60 mph on a light controlled freeway on ramp without TC when at the 190whp level. Have seen 7500 miles on an Emax, but many riders get 9k+.
Avon:
The Avon gives the best feedback of all of them due to the soft carcass, it is a very confidence inspiring tire. It has the best tip in / mid corner adjustment due to its shape. It also is the 2nd easiest to overheat and turn greasy, behind the G851. The Avon has the worst manners under 40f of all of the 240s. The Avon was also very difficult to use on the drag strip compared to the Emax, continually spun up 1st gear despite having VHT and a hot tire, As I recall, I never finished an Avon due to mileage, catching punctures in 3 in a row before switching to Emax.
TrashMax:
The G851 is trash and a "stuck in BFE need a tire and it's all they have" tire. Fast wearing, low grip, can't cope with the weight/torque, overheats crazy fast. A tire made for lesser bikes (Suzukis). Dead in under 3000 miles.
Metzler:
Metzler is pure mediocrity. Wandery, cuppy, terrible edge grip, unpredictable slip/grip on the cornering limits characteristics and overpriced to boot. Middle of pack feedback, middle of pack wear, middle of pack everything really. Dead at 4800 miles.
A lot of people don't ride quickly so the difference doesn't matter and a lot of quick people don't notice a lot of subtle feedback the bikes give, so it doesn't matter for them either. For those who ride on the bike's limit (not their limit), aka riders who are faster than the bike, on roads like Mount Lemon / Route 666 / The Dragon...it matters.