Pity the poor Link from Castle to Caps Ridge Trail , its just in the wrong place at the wrong time for most hikers use. The entire trails original purpose was to offer a non exposed route back to RMC territory for those who wanted to visit Jefferson as an alternative to hiking back along the exposed ridgeline during foul weather, unfortunately the westerly upper slopes of Mt Jefferson is not good territory for trails (I.E. The Link and The Cornice). Anyone who has been on the Link will realize that rebuilding it into a flat trail bed would be an incredible waste of resources compared to using these resources on far more popular trails that need attention. IMHO the main reason for hatred of the Link is psychological, it tends to be an afterthought by dayhikers looking to stretch out a nice day on Jefferson by adding in the upper Castles. Also people tend to equate a flat contour with easy walking, which definitely doesn't apply to the Link which is mostly an exercise in hopping from root to rock. Definitely not a trail runners route. Another strike against it is some rather optimistic map makers that show several streams crossing the trail on the end closest to the Castle trail.There may be water in the spring but for much of the summer they are totally dry with the only reliable water far closer to the Caps Ridge end. The last strike is although under cover, the trail is in full sun in the afternoon when hiking it and without a good breeze it can be quite hot.
These all contribute to many folks generally novice to intermediate ending up on the Link on a hot day with little or no water, hiking over rough territory. I generally try to warn folks off of it but generally its when they are skipping down the Castle Trail oblivious to what their detour entails.
I personally like the loop. I generally do it early in the morning and know what I am getting into. Its a good way to get some above treeline and still be done before noon.