Hi Chris,
I will take a stab (

) at your questions below.
How are armies generated? For example, if I wanted to game the siege of Dumbarton, how would I generate an army for the Britons of Strathclyde? Is the army generation system generic?
There is no "army generation system"
per se. Instead, you simply build your forces to suit your chosen scenario, based on your research and the number of figures you have available. For 28mm figures, a "standard" unit in HC will generally have a frontage of 160-200mm, and this can be scaled down for smaller figures if desired. Normally you would want four or more units per "division," and an army would comprise one or more such "divisions."
What would be the average game time for an average sized army? In other words, will the wife be calling at 1:00 am and then you have to convince her that, no your not drunk, but playing with toy soldiers.
The rules are designed so that large 28mm battles (16 or more units per side) with multiple players can be easily completed in an evening. If you are playing with one player per side, you can easily scale down the number of units to suit. Since you determine the size and scope of the battle, you can make it as large or small as you wish.
Does the game, as it stands, work with 10mm or will it need some basic conversion? I just have an itch to try 10mm. (Read: collectoritis is acting up again)
The game is easily adaptable, and includes an appendix with ideas on how to adjust for smaller figures. In practice, the key is the frontage of a "standard" unit. For example, I play Hail Caesar with 15mm figures on 40mm-wide bases. My chosen "standard" unit frontage is three bases, or 120mm, in width. For movement and shooting distances I normally substitute centimetres for inches, but that is purely a personal choice. Many players just use the distances as given, which definitely makes the game move faster!
Is it fun and fast paced? The reason that I got into WAB was that a certain 15mm ruleset was mindnumbingly boring to my usual opponents.
If that "certain 15mm ruleset" is the one I am thinking of, then I played it for about a year when it was first released. While acknowledging that different kinds of games appeal to different kinds of gamers, IMHO Hail Caesar is
much faster and
much more fun to play. Hail Caesar was developed from Warmaster Ancients, and while HC is a bit more complex than WA, it also retains many of the fun features from the earlier game, and plays nearly as fast.
Does gameplay feel right for Dark Age armies? At the moment, I only wargame the Dark Ages and am looking for a game that reflects combat in that era to some degree.
That isn't my period, so I can't offer any experience there. However, members of the Hail Caesar fan group in Yahoo who do play Dark Ages seem to like it quite a lot. The rulebook includes seven complete scenarios, and one of them is the Battle of Brunanburgh 937 AD. Here is a recent player battle report for that scenario:
http://satrapminiatures.blogspot.com/2011/05/battle-of-brunanburgh-hail-caesar-game.htmlHope this helps!
Cheers,
Scott
“What we wish, we readily believe, and what we ourselves think, we imagine others think also.”
~ Gaius Julius Caesar