As an interior and architecture photographer, my experience differs, I simply couldn't live without my TS-E collection. Every time I try to use my 16-35 instead (especially indoors) I am stuck with either too much floor or ceiling, the shift is useful as well to adjust the composition in relation with the elements in the frame. Sometimes I need a focal in between 17 and 24 and the zoom does it, but the TS-Es make my life much easier.
Optically speaking, both 17 an 24 are excellent. With the 17mm, be careful with flare when you face the light (that's my main complain about it) but it can be really annoying, the 24 is a bit sharper but to it doesn't really matter in real life, it main drawback IMO is the yellow / blue color fringing that can be difficult to remove completely in post.
With super wides, it is difficult to compose an interesting image; showing everything is not what I call a composition, so I would start to rent the 24mm for a try period.
Finally think as TS-Es as "tripod" lenses. Yes they can be used handheld, but critical focusing (specially with the 17mm) is difficult and better achieved on a steady image with live view. If used for architecture, you'll need time to "study your frame" and adjust the levels perfectly, and be able to use smaller F-stops and slow speeds.
Personally, I never take them for traveling, unless I am ready to carry also at least my small tripod.
Finally do not forget the golden rule with architecture photography : use a lens as long as you CAN and as short a you NEED.
Have fun with your experiments.