I believe that the net effect of these suggestions

[blade-soul]

Alright, I will bite on this topic briefly, from my personal opinion, albeit as a solo player.

A number of Veteran players may remember Winter '13 or Spring '14, a time before the alliance mechanic to Buy Albion Online Gold. There were still a number of alliances, however, they were completely part of Metagame. During this time, it was also before the Party System, so unit cohesion between guilds was difficult and yet that interaction still took place. This meant that despite friendly fire, guilds still actively engaged in metagame alliances against other metagame alliances. From these circumstances, the requests for an alliance mechanic were raised, and afterward the mechanic was developed and implemented.

So to respond to the first point in the OP, "Removing the ability for guilds to ally would greatly benefit the game", while a theoretical removal of the alliance system would lead to more natural alliances, it doesn't change the fact that such natural metagame alliances are possible now. The current system presents a large value in communicating current political relationships, both to allies and enemies alike. A side benefit of this increased communication is reduced logistical costs to operate multi-guild operations, as before implementation of the alliance mechanic, all metagame allied guilds were marked as red or enemy players, making large scale battles much more tedious.

In response to the second point in the OP, "Guild size/membership limit to say 100 players [would greatly benefit the game]", this point has been discussed many times in the forums. The two key issues this single limit would not address are (1) Professional or hardcore guilds would work around this limit by creating satellite guilds and (2) this promotes players working around the system. While a lower guild member limit would not directly limit the number of players in smaller guilds, in combination from the first point of the OP, these two points would further weaken intelligence, communication, and diplomatic activity gamewide. For a new guild or player to find officers in guilds can already be difficult, from experience, but now trying to find the right sub-guild that has the main leadership for a guild as well as determining the political relationships of these sub-guilds with other guilds is made even more difficult.

Finally, in response to the third point in the Cheap Albion Online Silver, "more Guilds fighting for available territories", I believe that while these suggestions may give the appearance of more guilds, in reality, we will still have the same large and small guilds, simply with a different organizational and logistical structure. The division would be more like platoons of players rather than a company of players (as for number of players per guild).

I believe that the net effect of these suggestions reduces communication of information for all players. It necessarily increases the frustration for any players wishing to participate in any inter-guild activities. The change will force players to find communication methods outside the game, both for managing larger scale conflicts (mini-map marks lose meaning), but even in day-to-day operations, as Guild chat will be less valuable and there would no longer be alliance chat.