Erm, plenty of manufacturers have low-ish power 2.5 litres, including VAG, so not really an argument! I have long argued the abarth is underpowered and doesn't at all deserve the abarth label, now used nearly as much as the once famous ghia name. However, at the end of the day, it's simply not supposed to be a hot hatch.
e.g. Audi A6 from 2004 still made 2.4 is 174 bhp a 6-cylinder 24v engine, Omega 2.5 is 164 odd, omega 2.6 is 175bhp odd. You find that a lot of 2.5 litre engines are not particularly up on the BHP, have a fair torquey punch across the whole profile and aren't awful in terms of economy. If Fiat wanted it to be a 2.0T with 220bhp+ I am sure they would have done it, but they didn't simply because it would approach their Alfa sector. A big company like fiat has to be ever considering such things.
It was unfairly compared to the Megane 225, the Golf MkV Gti, Astra VXR, Civic type R etc. because it is not in the same league, as most say, it's more of a tourer than a performance car. However, initially the motoring press tried to put it up against such models and wondered why it did so poorly - simply because it is in a different market. 170bhp now in a 1250kg+ car is does not get you into "hot hatch" when the bench mark is so high right now.
As a second hand buy, a used abarth is one of the best buys out there if you want a mixture of kit, looks and performance without breaking the bank, I however, wouldn't own one. Saying however that it shouldn't be in between a 1.8 hatch and hot hatch terrirtory is quite wrong - as a pre-regged car you could pick it up for pennies when compared to other marque's 1.8 hence why it was never a bad buy apart from the depreciation. I know lots of happy owners. Unfortunately, you are failing to see that a technical forum like FF mainly gets people with problems, looking for solutions and help and future support, it's not a particularly subjective viewpoint. Other forums are different of course, especially enthusiasts forums regarding more special cars.