I also have a T-7. I do not use mine as a pseudo-progressive press. I install dies and leave them. For example, in addition to rifle sizing and seating dies, I have sizing and seating dies but I also have things like a universal decapper and Redding Instant Indicator installed in the tool head.
I have no trouble with my priming system, large or small. I see no need for the roller handle or elevated mount*. If you want to spend the money to add these goodies, go for it, but they are not needed.
I have no insight into why people don't discuss them more. Maybe it's because they just work (mine does). Maybe it's because the T-7 is relatively expensive. Maybe it's because few have them due to cost given the cheaper options available. Maybe it's a combination of the above.
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* For me, the elevated mount would raise the press to be too high and would interfere with proper operation. I wonder if Redarts' low seat height, tall bench and elevated mount have created the situation where he wants a roller handle, as this just isn't an issue for me. Each person has to work out their own ergonomic issues.