Well for starters joining one guild should effect your eligibility for candidacy in certain guilds, for instance the thieves guild has no place for a cold blooded murderer who is a member of the Dark Brotherhood, sure they share some of the same skills however one would assume that those who would join the Dark Brotherhood have a penchant for murder where the Theives Guild has a strict no killing policy, thus any members of the Dark Brotherhood would be considered too violent to be considered for membership in the Thieves Guild
eh....if you only played Oblivion, I'll be lenient with you, but only this time. Frankly, the Thieves Guild of Cyrodiil is nothing more than a bunch of glorified Robin Hoods. In Morrowind, you were sent to assassinate people at points, namely members of a rival gang and some of their supporters. Various books in Daggerfall had interviews of TG members stating clear as crystal that they will break a freelancer's arms and hands, along with informing to the guard about the freelancer. Oblivion is the odd man out, the others had no qualms about using violence, save for when you are doing a job that involves stealing. Reason being, if you murder someone while on the job, the guards will make the guild's life much more difficult.
But you are right that join certain guilds makes it harder or outright refused from other organizations, and not just the whole silly MG vs. Necros or BWC vs. FG kind of crap
Secondly guilds should have tasks more in line with the theme of the guild, in Oblivion most of the Mages guild tasks revolved around dungeon crawls and fetch quests that required little to no use of the skills that one would expect a mage to have, even some of the later thieves guild quests devolved into dungeon crawls with the Grey Fox even waiving the blood price so that you may kill as you please effectively nullifying the need for stealth.
Agreed, and part of the solution would be having certain skills at a certain level, in order to gain ranks, other than doing quests.
And thirdly less linearity in guild progression, probably a minor point but it would be nice to be able to pick and choose your contracts and the order in which you do them with more contracts opening up as your rank increases.
Agreed
Am I the only one who finds noble assassins a tad cliche? An Assassin is little more than a hired killer, there is nothing noble about it. However I do agree that perhaps the Dark Brotherhood took it a bit far, the Dark Brotherhood is a bunch of murderers and psychopaths given purpose through some hokey religion however it would be nice to see a group of assassins who take up Skyrim's dirty jobs out of necessity and for coin rather than the fact that they are sick bastards who enjoy killing.
Don't let crap get in your eyes, the Morag Tong are hardly noble assassins. If anything, they're regulated assassins, and even then they will use "gray writs" to knock off targets certain people do not like that are under the "do not kill" list. Frankly, if they were allowed to run free, the Morag Tong would be just another Dark Brotherhood, except you would have to put up with LOTS of Melphala worshipers, as opposed to a wider variety of assassins whose main concern is money.
Also, when it comes to factions and organizations, I plea that people remove themselves from OB and look more towards Morrowind. Sure, there were organizations that opposed each other (Telvanni and Mages Guild), but there was less "evil guild vs. good guild" (that too many people are proposing), and much more organizations that like others, neutral with some, and hated others. So, while the Cammon Tong and Thieves Guild were against each other, the Fighters Guild could either exterminate them or not (depends on which route you took), and the Thieves Guild could get the help from the Fighters Guild to take down the CT and ask the MG for hired muscle.