How much do unique units and unique buildings matter? I mean. The red coat now has a measly 25% bonus to gunpowder units. That's it. And the unique building of the English a mere +15% gold over the standard unit. People beeline to the unique units and etc, but is it worth it for such a tiny difference? It's annoying, because one of my favourite things about this game is how the civilizations are different - I want a significant difference between them and their units/buildings.
Secondly, how important are resources? Very, obviously. But is it worth creating a city to get, say, fur and silver if it's right next to a bunch of tundra and ice?
Thanks.
In both cases, as always, the answer is, "it depends".
The situation will dictate the usefulness of UUs and UBs, as well as specific resources.
Slight differences--+1 strength (don't Redcoats still have that?) and +25% versus gunpowder can add up over the course of a campaign, allowing your units to win just a few more battles than they would have otherwise. +15% wealth doesn't seem like much, but put Stock Exchanges in
several cities with mature cottages and you'll see significant results. In my England games, I blast ahead of the competition in the mid-game right when SEs and, shortly afterwards, Redcoats become available (in fact, there's synergy there, the SEs boosting your research to allow the Redcoats to appear sooner).
That being said, some UUs and UBs are more worthwhile than others. Some are worth rushing towards, others less so. The Romans have a UU that's probably the best in the game, making a rush to discover iron working at the expense of all else wholly worthwhile. In comparison, however, the Celts' Gallic Warriors don't offer nearly as exciting a bonus over regular Swordsmen--so you can probably make IW less of a priority when playing as Brennus or Boudica.
As for resources--well, if you don't have silver or fur, and your cities are all at their happiness caps, then yes, a junk city on the tundra can be worth it, boosting your happy cap by 2 (4 with a forge and a market), allowing you to grow your cities, whip more population, work more cottages, run more specialists, etc.
On the other hand, if you already have a source of those resources, more may not be necessary--unless you need them to trade for other resources to, once again, allow you to grow your cities larger by either increasing health or happiness. Another scenario might be that you're trading for silver and/or fur, but feel that you're subsidizing a rival in the process. Gaining your own source of those resources allows you to end trade deals that you fear are benefiting your rival as much or even more than you.
Another scenario could be that your cities are well below your happiness caps--but you're planning a long, drawn-out war of conquest soon. In that situation, having a couple of additional happy resources might help you stave off war weariness long enough to finish the campaign comfortably.
The examples you gave are a little lopsided, though. By working a silver mine and a fur camp, I can usually pay for a junk city's maintenance. If the resources in question are deer and crabs, you may need to give it more thought (health usually being easier to come by than happiness). Early in the game, a city like that will be tough to afford. By mid-game, however, you should be able to easily afford it.