Not sure why a lot of people are disappointed in the engine power. Must have been the hype of 3.3l turbo that made some hoping for an AMG or a M serie Mazda. Of course it depends where the CX-90 is priced, but if it is priced to overlap a honda Pilot and an Acura MDX ($35 to 50K USD), then I would say the engine performance is right where they should be.
Here is how it stacks up against the competition (price based on lowest possible MSRP. Research done as quick as I could, there might be mistakes in there):
Volvo XC-90 Core base model: 247HP, 258tq ($57,095)
Honda Pilot: 3.5l V6 285 HP, 262 tq ($40,495)
Toyota Highlander 265 HP, 309 tq ($37,755)
Acura MDX: 290HP, 267 tq ($49,925)
Kia Telluride 291 hp, 262 tq ($37,255)
Volvo XC-90 Plus/Ultimate: 295HP, 310 tq ($61,995)
Ford explorer: 300hp, 310tq ($38,355)
Mazda CX-90 : regular fuel low output: 280 hp - 332 tq
PHEV: 323 hp - 369 tq
Premium fuel high output: 340 hp - 369 tq
BMW X5: 335HP, 332 tq ($62,595)
Acura MDX type S: 355 HP, 354 tq ($67,895)
BMW X7: 375HP, 398 tq ($78,845)
Ford Explorer ST: 400HP, 415tq ($55,835)
Volvo XC90 Recharge: 455 HP ($71,900)