No offense but there’s little to no chance that anyone would trade both Fenrir and Tao(or 2 x Kiel + Tao) for MOT alone, you may want to add something like zeny from your side, or to lower your expectation to something like 1 x Kiel + Tao.
There's two way to answer your comment: Pick which one is best:
1.) I'm not sure how you see things but, this is my card and that's how I see things. Period.
OR
2.) Nah, Fenrir and Kiel did not maintain their value, as evident to that, you see now GTB is more expensive than Kiel now.
Also not to mention that MoT did not just retain its value but increased as well it only gets better and better than before. Now in PvM, WoE or even PvP, MoT is very desirable, since most gears had their hard defense buffed, and since most new monsters also had their HP pool got very high like in bio5, makes MoT more desirable than ever before for the damage output...
Like I said, Fenrir did not retain its original value, and most people will tell you that now its kinda like a Kiel price. With all these gears that we have now, with FCT reduction.