I don't think we will find much foreshadowing, as that would imply they had the setting and plot of the next title 100% decided during the development of Skyrim, which I find highly unlikely..
sure, looking back you may see things as "foreshadowing", but it was not necessarily foreshadowing, and was very possibly just the result of the human mind naturally looking to make connections between similar things.. I mean, in Oblivion we heard just as many rumors of the various other provinces as we did rumors about Skyrim..
alot of those references may simply be due to geographical proximity.. in a world with no internet or telephone you are clearly going to hear more about a nation you border with than one on the other side of a war torn continent..
first, you should not take anything M'aiq says seriously, he is an Easter Egg whos entire purpose in the world is to reference various "community in-jokes" like the Fishy Stick or Colovian Fur Helm, and to talk about removed and unfinished content.. the Dragon reference was likely referring to the desire around the forums at the time of Oblivions development to see Dragons make a proper appearance.. I have heard others say it was hinting towards a quest they considered from early development that they never made that would have had you taking on a Dragon in a cave near Cheydinhal, although I have never seen data supporting that in the CS myself..
as for the blades waiting for a Dragonborn, I wouldn't really call that "foreshadowing" Skyrims plot either, the Blades entire purpose is to serve the Dragonborn, and with the last known one dying when Martin sacrificed himself, what else would be left for them to do but wait? if you job is to serve a customer, but you have no customers, you wait for one to arrive
see, foreshadowing can work in a series that comes out every year or two like Assassins Creed, but not with something with something with as sporadic of a release Schedule as TES.. because to properly use "Foreshadowing" you have to have the setting and most of the plot already decided on by the early-mid stages of the game prior to it's development..