there isn't any reason not to add it as a feature, it wont cost anything other than paying a programmer.. and i also get the feeling that it will definitely be included, just not for a while.
i think not including whatever sampling becomes available initially is a good idea... the digital osc aren't as robust as those in the evolver...no idea if this would effect sampling possibilities... and the synth is centered around synthesis and can even be used as a 6 voice polyphonic synth so people really should dig into programming it and not be distracted by the ability to put samples into it
i get the feeling the use of samples is really just there to add something to the sounds you program, i've gotten really impressive results layering the same 2 sounds but with different levels each, the differences in sound of the same 2 samples at different volumes was impressive.
so the Tempest will be synthesis focused and the Linndrumm2 will be sample focused... at least that is what i think
digital envelopes and limited sampling aren't a huge deal when you think of it as a total package. i think its the coolest drum machine ever made, i've never even thought of getting an 808 or something affordable like an electribe.. but the tempest is something i'm definitely going to consider