>>10436326Reissues seem to be done for very popular figures that sold super fast. So far they reissued the grey knights, vitrix guard, and the heroes of the chapter UM. Vitrix did sell out very fast and became a bit hard to find after. Grey knights didn't seem to sell quite as fast, but did shortly become harder to find as well.
I could see guitar man not only selling fast, but getting a reissue, seeing how he's as close to a main character as the line has.
But because he's over $100, I don't think he will completely sell out everywhere, so you should be safe in waiting. That's just my opinion, and others might recommend to buy now.
I suppose you should check out the dreadnaught and paragon war suits, plus a few marine reviews to get an idea of what the line has to offer, and how guilliman should turn out, if your that worried about needing to preorder.
Rarely has anything been significantly discounted, besides stacking AliExpress coupons.