Re: point 2) by Mauro:

Lecturers often teach more than one subject per term, even more often they teach a subject in both semesters. Most lecturers are also researchers. This is essentially doubling their commitment as a lecturer. It would also be unnecessary for optional subjects which already have low turnout, whether due to the number of students they are open to or due to the interest in them, to be ran twice a year.

Re: point 3) by Mauro:

Every sane person who has went through the first year of Electrical/Electronic Engineering will testify that extending the possible hours to shove lectures into is a terrifying idea.
On the other hand, those extended times could cause havoc in part-catered halls, as there are certain times the canteen is open for breakfast and dinner, I don't remember them anymore sadly.

I agree with the previous comments that the timetables are too scattered. I have a few more points having been here for 4 years now:

1) It seems to me that timetabling is done via a scheduling software but then it is not checked by people or it is checked very briefly. I say this because at any one time you’ll see that there are A LOT of empty lecture theatres, I wouldn’t be able to give an estimate but if you just try and have a look around you’ll see how many rooms are not used at each hour. Often, these unused rooms could fit lectures that are delayed to later that day or that are moved to far away location. This is incredibly inefficient in my opinion. Also, it is possible to make timetabling change, however the system is very hard to work with. During my time at UoS lecturers managed to change lecture theatres to other ones and in other slots, BUT the issue wasn’t the availability of rooms (I personally went and looked at rooms’ timetables), rather it was the total inflexibility of the timetabling team which seems to prefer to say no, rather than check if something is durable.

2) Many, Many issues could easily be solved by scheduling modules to repeat in both semesters. This would allow multiple things: i) lecturers would be more prepared and material would be more steadily available ii) students would spread out more evenly because they would be able to pick modules in different semesters. Usually the busiest modules I’ve been with in the first semester were not a prerequisite for modules in the second semester (MATH). Also, often people are forced to take busy modules exactly because they have to pick 4 modules each semester, but if you could pick some of them the next semester, that would help.

3) Finally, although most students would disagree with me, I think lecturing hours should be extended. Currently we have 9am to 6pm which are 9 hours a day, yet we have a lot of timetabling issues. If you look at most European universities they adopt a different strategy, where they start lectures earlier and finish them later as well. A good lecturing time could be from 8 to 7pm. This would allow for lectures to be scheduled much better and, I believe, paradoxically we would have fewer lectures very early in the morning and fewer lectures very late in the evening. 

Not advocating 9am to 6pm lectures, but in later years when contact hours are reduced travel to and from university starts to become comparible to the contact hours. Especially for those who do not live within a 15 minute walk from the university, and those who have to commute by Car/Train. 

Fragmented timetables can also make untimetabled academic commitments difficult or unworkable. Masters students general have a project encompasing the whole year in their final year. In many cases, it is best to spend an entire day just working on that project, and in some cases it may be essential to have 8 hours to work on something, for example if you are carrying out experiments in a lab.