Then to address the OP's points about armature and or very slow cyclists that may not wish to use the roadways. I personally have no problem with sidewalk bicycling or MUP's & Sidepaths (AKA = sidewalk bicycling a little polished up for show).
PROVIDED IT ISN'T MANDATORY IN ANY WAY INCLUDING PUBLIC PERCEPTION !!!
Who am I to tell someone else that if they prefer they aren't allowed that option? So long as they aren't trying to attack my road rights not a problem (unfortunately some of them do actively attack my road rights including at least one pro-path group in a nearby town that actively sought mandatory use legislation to force cyclists to use their path after they got it built).
I do have some very strong feelings about what "rules of the path" should govern such facilities since I myself even use them from time to time when they are at some times a better option then the road for some stretches (one rails-to-trails path specifically which is a very good path along a very, very, very bad road for cyclists). These are as follows along with the "Why" of them:
#1 = When you mix pedestrians and cyclists (along with other similar modes such as roller-bladers and skate-boarders) together it must be clearly understood that cyclists (and other higher speed users anything from sprinters to roller-bladers and skate-boarders and should not run-down, close high speed pass "buzz", or otherwise harass pedestrians (or other lower speed users) !!! This is extra especially true with conventional sidewalks as apposed to MUPs because they are far more low speed pedestrian dominant structures with usually much less room to maneuver and many obstructions and conflict points. It's no different a situation then cars vs. cyclists on the roads the faster users should show extra care and respect around the slower and more vulnerable users and should not endanger or harass them !!!
#2 = On MUPs especially all users peds., cyclists, and others must understand that multiple users operating as a "pack" side by side blocking the whole path from edge to edge in both directions of travel so no-one can pass them and "charging" at traffic coming the other way is not acceptable behavior is very uncivilized and not in any way in line with common respect and courtesy. Most MUPs I've seen are 8-foot wide or so and represent basically two unmarked lanes of travel yet users of all types peds., cyclists, roller bladers, skateboarders, etc. . . seem to just love to take up the whole path from one edge to the other with zero respect for anyone coming the other direction or trying to pass. Even when cyclists "take the lane" on a public roadway with the very small exception of a handful of one-lane, one-way roads they do not take up the whole road from one edge to the other so no one can get by them either direction. At most they take up the right half of the road (two lane road) leaving the left half of the road open for oncoming traffic and to allow others behind them the opportunity to pass when there is a break in oncoming traffic. For some strange reason this very basic level of common courtesy seems to go completely out the window on MUPs and that needs to be corrected and doing so infringes on no-ones rights but rather improves the situation for all users.
#3 = It is critically important that traditional pedestrian dominant right of way and legal protection be preserved and enforced for all side-walk and MUP crossings of vehicular roadways. The traditional crosswalk right of way model dictates that cross-walk traffic always has dominant right of way except for at signal light controlled intersections where there are crosswalk "walk"/"don't-walk" signs wired in synchronization with the vehicular roadway signal lights. Long story short, vehicles on the road yield to cross-walk traffic NOT the other way around. This is an incredibly important thing to preserve for the future of our society that is under sustained and nearly overwhelming attack by a belligerent violent aggressive motorist first mentality. When they put up stop signs for the path traffic and make the vehicular road traffic have dominant right of way at an MUP crossing of a vehicular roadway an incredibly dangerous and utterly malevolent legal nightmare is created for all users of such an MUP pathway making it such that anyone using that crossing that is struck by a motorist on the road is always in the wrong and has no legal rights whatsoever !!! Such crossing effectively become "legalized killing zones" where vulnerable MUP users can be run down at will by motorist with little to no consequences. This is the diametric, complete opposite of traditional cross-walk right of way !!! Now, it is true that higher speed MUP users such as cyclists, other wheeled users, and even runners do represent a potential conflict if full traditional crosswalk right of way standards are used at MUP crossings. This is very easily and simply addressed, however. All that is needed is a simple "slow to walking speed before entering crossing" standard of conduct, legal encoding, and signage for MUP crossings to allow them to function with full traditional crosswalk right of way and legal protection for vulnerable users right of way standards. That produces the optimal "mutual respect" kind of climate that makes for a safe transportation system. Thus at MUP crossings that are not signal light controlled intersections vehicular traffic is required to show respect for cross-walk users as normal (with "State Law, Yield to All Cross-walk Users" type signage) while path users are also expected to do their part (as clearly indicated with ("State Law, Slow to Walking Speed Before Entering Crossing" type signage) which allows vehicular road users the opportunity to properly yield to cross-walk traffic so they don't have some cyclists "come flying out of now-where right in front of them" in the crosswalk and they can't stop in time to avoid hitting them.
#4 = It is ridiculous that many signal light intersections are set-up with pedestrian (and thus MUPs and sidewalk cyclists as well) crossing signals that do not work unless you push the button and the button often gets broken !!! Crosswalk "walk"/"don't-walk" signals should function with every light cycle automatically and require no special triggering !!! As for the buttons they should exist but should be there to trigger signal lights that are sensor based and only an additional way for side-walk/side-path users to trigger the light not the only way !!!
Do those things to address the problems that side-path type infrastructure creates and it would be a benefit for everyone and make our overall transportation system far better for everyone.