I like to load my characters up with items, so I would recommend considering The White Cloak and the talisman of protection for those sweet 5+ ward saves. I'd also take a shield with the BSB and general if you can to get his armor save to 3+. You haven't got a mage, which is fine - it's most efficient to either have no mage or a level 4 - and the ulrican prayers seems pretty good.
I would almost always take a grandmaster over a general, but since you're on foot the general is pretty good. I'm no convinced about the usefulness of the mace of helsturm, I think I prefer the sword of justice, but it can be a good choice if you anticipate difficulty with single, high-toughness, models.
I would probably ditch the greatswords, take a mortar/hellblaster alongside your cannon, and take an engineer for rerolls, but I understand that they're important to the list thematically. I'm actually having a lot of trouble fitting in greatswords when our core is already so infantry heavy. I find myself taking things like demigryphs, outriders, and knights.
The most impressive thing on the empire roster is the steam tank. I think it's a must-include for tournaments. But if you're playing with friends it would probably be unfriendly to take one in a 1500 point game.
I'd love to know whether the veteran upgrade is useful. It seems unnecessary if you have a character nearby. I think Archer screens is a good idea, at least to take away first chargers and/or to redirect.