Possibly if you'd done all the work yourself you might feel better about it (it's always easy to expect more from experts) but hopefully it is a case of waiting for the pads to bed in fully (over the course of several weeks normal use - no hard stops as that will overheat and glaze the pads).
Then bleed the brakes again - the old two-person way is always effective (I have a Gunson Eezibleed pressure setup which doesn't really fit the reservoir properly - I use it with the bottle empty just to pressurise the reservoir, rather than to try and automatically fill it).
Both my Spiders have impressive brakes - light and very little pedal travel - with my 156 being nearly as good (it has a full set of fairly new discs/pads), but I am told they're all rubbish by someone who drives a 1991 Nissan Bluebird. His brakes are amazing - original discs (massive ridge of about 3mm, grooves from wear) brake fluid never changed but pads replaced five years ago. And he's right, the Nissan will lock the wheels with very little effort on the pedal, so yes, we are just wasting our time and money on the vanity of having new brake discs. They'll never be any good compared to the puny discs/drums and no ABS on Japanese cars
but as far as the Alfa goes, they'll be the best you can get. It's a heavy car but those early Bendix/ATE setups are a big disc, more than sufficient, they're as big as you get on a BMW 525 of the same era... interestingly it turns out those have crap-feeling brakes too!
If you measure the brakes by how little effort it takes to feel sharp braking, any old Japanese or new budget car will win any time, and meanwhile the MOT test requirements are ridiculously low anyway. Actual braking from 100+ mph might give quite different results. I've tried to convince my friend that his brake fluid might boil and his discs might warp or shear during hard use, but of course, why fix what isn't broken...
To focus the mind it might help to consider test results from when the GTV was new:
Autocar, 27 March 1996, 2.0TS, 70mph to 0, 52.2 metres
Performance Car, October 1995, 2.0TS, 70mph to 0, 168 ft. (51.2 metres)
Top Gear, September 1999, 3.0V6, 70mph to 0, 48.7 metres
In the same test, an Audi S3 scored 46.5 metres and a Lotus Elise 111S scored 54.3 metres.
The Elise is a much lighter car, so its brakes must be especially bad...
See also http://www.youtube.com/watch?v=KGkKDaYd3Mo
and note the 'highway code' figure of 244 ft., and the Lexus result of 139 ft. And the Porsche result of 170 ft., about the same as the 2.0TS GTV, then...