I know I might be buggying with this question which has been discussed before so please forgive me!
I can not help as I can see many possibilities with this feature, and I never felt that the previous discussion where absolute conclusive.
Is there, in any way, a possibility that you would consider adding a two block signal?
Let me back up my question with why I think it is an important feature of signalling. I wrote the long post a page or two ago, which held some arguments, but this should outcome shorter!
The two block signal would be redundant on simple signal layouts, as the existing signals would cover that perfectly fine. It is in more complex layouts and where you start to mix different working methods when directional reservations would not suffice, and the two block signal would come in really handy.
As an answer to the fact that you can build your way around it, I admit that nothing, including the scenarios below, is impossible in the existing state of signalling. It just demands more trackwork, which in turn means that more land is occupied, more track is bought and potentially more signals are used, ie more 'clumpsy' and it takes more time to build (adding second track lead, setting up one way signs etc).
Regarding how a player intuitively would build a signal layout, I think that higly depends on what tools the player is offered. If there is no such signal, the player would probably just build as you suggest (every token block stretch has a doubble tracked lead), but if the player is presented a way to avoid doing that, I think the feature would be used.
Uses of a two block signal:
* If a station serves different lines with different working methods, or even two or more token block lines.
Imagine a big goods hub with lots of industries around. Only one single track is needed to each industry, but each one would require the doubble track lead the length of a train out from the hub which might doubble the size of the station. With some smart track work you could combine some of the returning leads or make some platforms specific to certain lines, but it might easily become messy. Alternatively, you could just use absolute block directly from the station (asuming there are no intermediate stations on the single tracked lines), but that would require another signal in the other end, potentially including a signalbox. If you just put one train staffs directly on the platform ends, you might be blocking tracks for other trains and if you put it on the single track line with no doubble track leads, the track is not secured properly and deadlocks may occur if you operate more than one engine.
Also, one train staff is in fact the most intuitive to use in this situation, since this is exactly what one train staffs exists for: Signalling dead ends.
* When creating signal gates with multiple branches and line crossings, you sometimes dont want trains from a certain direction to hold at a specific stop signal, blocking other traffic either because it is lesser important or it creates hinder for other trains. This one is difficult to explain, as the need would be very subjective to the actual situation. There might be a number of reasons for such a situation to arize, be it many entrances close to a station, or signals in general in tight space.
* If station signal is "two block signal", pakset author can balance in signal speed. The station signal only allowing slow speed for safety reasons and the (expensive) exit signal allows for higher speed. This is a pakset decission, I admit, and could be completely omitted with no other impact than it being less realistic for swedish purposes. But if two block signals become a reality, I will do this with them.
* When going single track to a termini (with token block and no doubble track leads) you dont want more trains than there are tracks available at the termini to be sent. Therefore, a two block station signal and a two block exit signal (token block) from the previous station and then the choose signal in front of the termini would create the desired effect (this example would require that two block signals are 'stackable', ie two "two block signals" in a row would effectively make the first one a "three block signal"). Admitted, if you make the doubble track lead at the termini it would at least add a buffer (but not fail proof, since the train waiting at the lead would have to pass a signal in order to resolve the reservation behind it, allowing a train onto the line, even so if it is in the wrong direction). If the line has no intermediate stations, you can use choose signals directly on the previous station, thus completely eliminate the problem, but in this case, token block is needed.
Again, forcing the player to make the doubble track lead (in the token block case), creates some less slim designs.
Also, this could be resolved by the player creating proper schedules, however misstakes and misshaps happen and it is easy that something goes wrong. Even with this possibility, player would have to administrate proper schedules!
* Some bonus side effect would be that instead of waiting at the token block signal on the double track lead, the train can be held at the station platform for a longer period of time, allowing for longer boarding. That might even be more time efficient since the train dont have to stop twice (one time at the station, one time at the token block signal).
I think I already described it, but I imagine a setting in the dat file is_two_block_signal=1 or something similar, which would allow the paksetauthor to use it on any type of signal.
The two block "search" for next signal would stop at next signal or end of choose sign, alternatively another special sign.
What do you think?