I loved the book (in theory). It was full of some really new, experimental things. In practice, not all of them were good- if used as written, Comeliness is a massive buff to Elven PC's and obnoxious to deal with (especially with the section about Evil aligned people liking negative Comeliness....I need to mention that in my alignment thread...). Thief-Acrobats were a neat idea, but in practice only good for one thing, if you can parse how Dodge is supposed to work. Barbarians and Cavaliers were powerful, but the limitations on their behavior made them difficult to actually play (the fact the Barbarian gets so much of the stuff people seem to think are "Ranger" abilities never fails to amuse), and the new spells and magic items run the gamut from "neat" to "what the?" to "unusable trash", lol.
The polearms were just "whatever", but I have a friend who is enamored with the glaive-guisarme and bohemian ear spoon is so much fun to say, lol.
The expanded multiclassing was just incredible though, with some very creative options for PC's, like Halfling Druids, and I was sad to see these excised from 2e.
As for specialization...I never had a problem with it, the semi-random nature of what magic weapons you have mostly disincentivized you from sinking a lot of resources towards one kind of weapon. This was, strangely, the hardest thing for the people I played with (myself included) to learn. I would pore over the weapons available to select what I thought would be the "best" one, and then fail to find magical versions of it.
Even if you chose the perennial favorite of "long swords", if your DM used published adventures, those would always occasionally have really powerful weapons that nobody was proficient in, lol. +1 long swords might be plentiful, but some of the strongest weapons I'd ever encountered were bastard swords, tridents, warhammers, scimitars (both speed and the Flying Scimitar of Kusmit!), and lances.
But don't worry, Snarf will inevitably see this thread to tell us all how absolutely wrong we are to like UA, lol.