A tablet that's 2 lbs and > 0.5" thick is gargantuan by today's standards. Less so at the time of the original Surface Pro release, but still huge- it was 50% heavier than, and 1/3 thicker than its main tablet competition at the time (the iPad 4).
I think the extra size and weight is totally understandable given that it's a full-blown PC, but Microsoft's marketing message is that this is something that will replace both your laptop and your tablet with no compromises. They've used that phrase a lot (no compromises), but to a heavy tablet user the extra size and weight in tablet mode would've seemed like a huge compromise. 1/4 lb isn't much of anything in absolute terms, but in relative terms for that product category the hyperbole is probably warranted.
I think the extra size and weight is totally understandable given that it's a full-blown PC, but Microsoft's marketing message is that this is something that will replace both your laptop and your tablet with no compromises. They've used that phrase a lot (no compromises), but to a heavy tablet user the extra size and weight in tablet mode would've seemed like a huge compromise. 1/4 lb isn't much of anything in absolute terms, but in relative terms for that product category the hyperbole is probably warranted.