You're disregarding historical precident in your conclusion. Hammerfell, refusing to agree to the terms of the peace, was expunged from the empire and repeatedly devistated by the Aldmeri. Hammerfell isn't in danger of being invaded. Half of it is occupied...
No I'm not. You simply lack a firm grasp of the relevant lore. None of Hammerfell is occupied. The Aldmeri Dominion sued for peace and withdrew all of its forces pursuant to the terms of the Second Treaty of Stros M'kai over 20 years ago. I also never said Hammerfell was in danger of being invaded. I implied the exact opposite in that the Aldmeri Dominion could be leaving it's borders underdefended by taking a circuitous invasion route to Skyrim with such a large portion of its armies. Hammerfell has had over two decades, almost as much time as the Empire, to rebuild its infrastructure and armies and the threat of Hammerfell and/or the Empire taking advantage of the absence of such a large portion of the Aldmeri armies is plausible enough that the Aldmeri Dominion would have to factor it into any invasion plans.
Invading Skyrim from the north would involve storming beachheads, sure, but in all the north, only Solitude is in any position to offer up any resistance, Dawnstar and Winterhold being virtually defenseless in their current state, even before the civil war.
First of all, if you understand the geography of Tamriel, you would realize that all fleets must pass Solitude and it's lighthouse and would easily be spotted for miles from the vantage point of the capital city. They would be open to attack from the Skyrim navy before even making landfall and in general their presence would be known long before they could make landfall further along the coastline. There's no chance of an element of suprise that favors the Aldmeri Dominion as it did when it made landfall in Hammerfell during the Great War
Second once one passes Solitude one enters the Sea of Ghosts which are noted in the lore as "ice choked", i.e filled with hazards such as icebergs further out from the shoreline, while the shorelines themselves are largely rock lined and dangerous to navigate (observable first hand in the game). Winterhold in particular is insulated by shoreline conditions precipitated by the Great Collapse.
Third, there's no reliable basis to assume that Dawnstar is virtually defenseless and even less so to speculate that it would remain so. The meager number of guards and population in general is a function of scaling to make the game playable and to scale the cities relative to one another. One shouldn't read into it that there are literally only a handful of guards garrisoned there unless one is also going to assume that an invading fleet is only going to be constituted of a half dozen ships. If it were that easy then the Empire would have assaulted it from the sea during the civil war. At one point it was a garrison city with walls and a fort and it's not unreasonable to assume that it would be refortified by the Stormcloaks.
One final note, the distance by sea from Lillandril, the closest port city on Summerset Isle to Skyrim's northern shores is over 1,000 miles by sea from Solitude, but that's straight line distance and staying close to the coastline. Conventional navigation by sailing doesn't allow for a straight line path. While it would be extremely generous to attribute the speed of a fully loaded 15th century carrack to an Aldmeri Dominion warship, even if we did that it would still take an Aldmeri Dominion naval fleet approximately 2 weeks to reach Solitude under optimal conditions assuming they never set anchor along the way, and a few more days to reach Dawnstar.
The allocation of soldiers to each ship would therefore be relatively small for such a long trip as it would require the ships to stock more provisions to sustain the crew and soldiers for such a long duration as well as for the initial days if not weeks of an invasion. There is nothing in the lore to support the notion that the Aldmeri Dominion has ever possessed a sufficient number of ships to accomplish such a feat. Contrary to that, the use of the Aldmeri Dominion navy for amphibious landings during the Great War was minimal compared to the number of soldiers that made the assault over land. Even if it did, there's still an additional problem created by the large distance which is a supply line or, more specifically, the lack thereof.
That said, there's really no reason to assume that the elves would stick with a one sided-assault. Morrowind is in complete shambles by all accounts, and is in no position to even slow down a determined army passing through a sliver of territory before assaulting Skyrim from the East, while Hammerfell has been occupied since the great war.
Neither is a viable option. Hammerfell is not occupied. Morrowind is under the dominion of Argonia. "All the texts" you have read are wrong. There is only one narrative from the lore regarding Hammerfell and the Aldmeri Dominion after the Great War which is the book
The Great War by Legate Justianus Quintius. It is the definitive lore on the subject matter and categorically states that the Aldmeri Dominion withdrew its forces from Hammerfell. It's beyond a great leap of faith to think that the Aldmeri Dominion could march through Hammerfell unopposed. It's delusional.
You said that strategically it makes no sense to move troops so far away from home, but I'll point out to you that historically empires have sprung up right here on Earth by doing that very thing.
No they haven't. If you can think of one example from history of a realm that sent the bulk of its armed forces on a long naval route to faraway shores while under the potential shadow of assault by realms on its borders then go ahead and cite it. The British Empire certainly never did this which is why your comparison isn't even remotely analagous.
We all know how sloppy Bethesda can be. Look at the companion sage for a prime example. A total disaster
