I prefer random missions from eu3. They were less linear.
They were good at times, and terrible at other times. The problem I had (and still have, since I still play it fairly often) was that there was only one mission available at a time, so if it made NO sense, you were stuck with it. Refusing a mission cost you 5 Prestige, and then you couldn't refuse another mission for 5 years. Too often, the "Make Bohemia vote for us" mission (impossible without cutting Bohemia down to 4 or less provinces in one or two wars and then vassalizing them in the next - even less practical when they're allied to France or England) would be replaced by "Naval Race with England" (when you have a Naval Force Limit of 2 ships) or something similar that your country wasn't capable of doing for at least another century. Too many of the missions were either suicidal, pointless, or just stupid under the present circumstances.
I got a "Build an army for our nation" mission last night, where my poor provinces can barely support an army that's just over half of my force limit. It will be half a century before I get the tech upgrades to boost my income to the level necessary to support an army of that size, and it would STILL be a poor use of funds for a trivial Land Tradition reward that will decay to negligible size in just a few years.
Combine the limitations of a single mission with the system of prioritizing certain missions, and that mission you refused might keep coming back (I refused "Make Bohemia vote for us" twice already, and if I refuse the current mission, I KNOW what will replace it), because the developers gave it a high priority. Priorities were mostly given in orders of magnitude, so a low priority mission would be 1/10th as likely to show up as a medium-priority mission, and 1/1000th as likely to appear as a high-priority mission. If you didn't WANT to do that high-priority mission, your options were to either keep refusing it every 5 years for a loss in Prestige, or else quit and reload an average of 1000 times before some particular more desirable mission appeared. Weighting some missions higher than others makes sense, weighting them to the point where it's highly improbable that anything else will happen, no matter how improbable or undesirable the mission may be, is blatant railroading. Giving you only one bad choice that keeps coming back over and over is annoying.
There need to be several missions to choose from, not a single mission as in EU3., and completing it should force a revision of the other choices, so picking one might or might not result in another interesting mission vanishing.