I've now played two games of Conquest of Nerath since the weekend.
One two player alliance game and another 3 player alliance game with
myself playing two nations.  I won both.

Both the games got as far as 13 victory points when we decided to call
it, since at that point it was very obvious who was going to win
making it pointless to play any longer than that.

The main criticisms that came up were:
- Board gets too clustered too easily
- An aggressive first player seems to be able to dominate the game
from the beginning
- Gaining income for conquering spaces is a double whammy to the
opponents who also lose income leading to a steam roller effect which
means other players can find it hard to get back in to the action
- Players are reluctant to buy footsoldiers due to them being fairly
ineffective and since Warriors/Wizards don't cost significantly more
- Dragons and Castles are too cheap
- No viable 3-player free for all mode
- Not enough dice!  Often you're rolling a huge handful of dice, so
while combat is supposed to be resolved simultaneously you're
inevitably waiting for the dice (of course most gamers have huge
numbers of polyhedral dice, so not such a big deal)

Some suggestions for improvements and house rules:
- Change the order of play after everyone has had a turn, by either
rolling a d20 for 'random' initiative or in order of how many
territories each player has (rolling for ties), or maybe something
else
- Don't start the game with all the figures in play that it suggests.
Maybe just the figures on the capital cities as well as any starting
footsoldier figures.  Would make for a longer game, but would mean
it's impossible to steam roll from the beginning
- Cap the number of units available to the number of figures you have
- Distribute a single random treasure card to each player at the start
of the game (I find it unlikely a nation would have no treasure to
begin with)
- On capturing a castle the loser of the battle makes a save check
(10+ on a d20) and loses one random treasure to the victor if they
fail
- Make all units except footsoliders 1 gold more expensive
- Set a base income of perhaps 10g for each nation so long as they
hold their capital (regardless of losing land). Extra income can only
be generated by conquering enemy lands.

I'd like to play a 4-player free for all as I think that could make
for a more interesting game, though I imagine that the last player to
go would be basically be screwed by that point.  Some of the above
house-rules could alleviate that.

In conclusion, while I like the game because of it's branding and
novel ability to 'dungeon delve' during a war game, I feel that it is
basically D&D branded Risk done badly.  Overall though, I'd give it
6/10 and would like to play it again.