Again let me preface this with saying that this is just a wishlist. I went down the Rabbit hole a bit with this. Also in most cases I like the writing for COC2. I wouldn't care if it wasn't mostly good.
The Wayfort as it stands isn't a very impressive or defensible home being essentially just a Motte and Bailey (Keep and Wall with a courtyard) with one Watchtower. The Keep seems to be square and doesn't have any bastions or surrounding towers for to split advancing troops and subject them to enfillading fire. The wall doesn't mention any towers either although they are necessary for visibility, improving range for archers and artillery, and providing defense for the mages / archers within. I feel like Matiha's office has more description than a lot of the areas in the Wayfort even though its the seat of your power.
War means refugees and refugees are drawn towards safety. Its a good opportunity to develop the fronteir either by establishing a larger fortification with some of the improvements I've mentioned, a fortified settlement, or creating new villages and farms within your territory. Ideally something Mythic and Legendary would be nice.
There are so many cool castles out there. Some withstood legendary sieges. In the siege of Szigetvár 3000 Croatians and Hungarians stood against 100000 Ottomans in an river fort with 2 Ravelins connected to a bastion fort. The Ottomans took the fort but at the cost of 30k casualties over the course of 33 days.
en.wikipedia.org
In COC2 flying enemies are a real concern. In WW2 when airpower was in its infancy Britain built towers with special guns at regular intervals around their naval bases. I would imagine that the wayfort would need similar defenses. Based on the descriptions in game the wayfort currently has a keep, a wall, a bridge, and 2 gates as well as a courtyard. The bridge should have towers along its length and a gate at the end to defend the river crossing. The wayfort definitely needs walls to defend against ground forces (corrupted centaurs, minotaurs ect) but other than the one watchtower there are no real air defenses. Annika mentioned using followers of Sorra to create a storm. Maybe that's also a possibility through magic.
Almost all successful defensible forts in history have been on elevated ground with access restricted. The ones that last a long time including one that lasted for 33 years can be supplied by fortified harbors. The Portuguese used to build stone forts on any conquered territory that could be supplied by the sea and that is how they maintained their presence in the face of numerically superior enemies (that and superior artillery).
In order to defend against siege towers artillery is needed and towers extend the range and visibility of artillery. Another tactic that could be employed on flat ground is that of multiple walls. Not only would this give the advantage of more towers but if the enemy broke through one wall they would be stuck between walls and subject to enfilading fire.
River fortifications are not unusual nor are river forts (the Romans had a system of linked forts along parts of the frontier) but in general successful fortresses are elevated somehow while fortified settlements are on rivers. Rome (Tiber), Vienna (Danube), Paris (Senne), and London (Thames) are all settlements either adjacent to or with Rivers running through them. The Danube has many settlements along its length. Its not impossible to have both a Castle and a Settlement like in the case of Edinburgh Castle.
Also the Wayfort can't really be resupplied easily. It sits along a river that Farrah mentioned had only a single ship travel through it. Tangier, Ceuta, and the Portuguese fortresses in their maritime empire were all supplied by the sea. Off the top of my head the torii gates of the Kitsune or some sort of secret passage (Predjama Castle was ressuplied through a cave).
https://en.wikipedia.org/wiki/Predjama_Castle
Notable Castles for Inspiration
https://en.wikipedia.org/wiki/Edinburgh_Castle (Endured 26 Sieges according to a Study)
https://en.wikipedia.org/wiki/Krak_des_Chevaliers (Concentric Castle. Also built on elevated ground)
https://en.wikipedia.org/wiki/Petrovaradin_Fortress (River Fortress)
en.wikipedia.org
en.wikipedia.org
https://en.wikipedia.org/wiki/Corfe_Castle withstood 2 sieges
https://en.wikipedia.org/wiki/Predjama_Castle Cave Resupply
Notable Sieges (Notable Sieges show which fortresses were actually useful and defensible as well as what fortifications were effective)
https://en.wikipedia.org/wiki/Great_Siege_of_Gibraltar 7.5k British vs 65k Spanish and French and 49 ships of the line 3 years 7 months long British Victory
https://en.wikipedia.org/wiki/Siege_of_Szigetvár Saved Vienna. Lasted 30 days 3k Croatians and Hungarians vs 100k Ottomans
https://en.wikipedia.org/wiki/Great_Siege_of_Malta 40k Ottomans vs 6k Knights Hospitaller "6,100, including militia, servants, and galley slaves" 4 months Hospitaller victory
https://en.wikipedia.org/wiki/Siege_of_Candia 120k Ottomans vs 30k Venetians 21 years length
https://en.wikipedia.org/wiki/Siege_of_Thessalonica 8 years 20k casualties Ottoman Victory
https://en.wikipedia.org/wiki/Siege_of_Ostend 3 years 100k casualties yet another example of a fortification ressuplied by sea
https://en.wikipedia.org/wiki/Siege_of_Tyre_(332_BC) 6 months
Its worth mentioning that Malta and Gibraltar consisted of multiple fortifications and settlements.
Walls:
Constantinople had the Theodosian Walls and Rome the Aurelian Walls.
