It is a good question.
Though many spices, herbs and aromatics do change with long cooking they do cook into depth, i.e., they create a base of flavor depth from which to work--or to leave alone. (I tend to do the latter, adding or offering flavor notes in other ways, post cook.)
There are several ways to play this, alone or, often, in conjunction with others. One way is certainly to eliminate the superfluous stuff. Imo, paprika isn't worth bothering with unless you need to bulk up your rub. Its flavor doesn't doesn't hold up to long (or even kind of short) dry heat cooking. Ground mustard is utterly useles in rubs. It needs water to activate the compounds necessary for its flavor and heat but the application of heat during cooking will cut that off at the knees anyway; long cooking diminishes it to the point that it adds nothing--so why use it in the first place? Prepared mustard can work as a glue for the rub but as there are other ways to handle that, it's a waste as well, imo.
Wet or paste rubs can make a difference. I use them alone or with a dry-over-paste approach. This can go a long way toward flavor maintenance. Oil isn't vital (I use it for poultry for other reasons) but you can use it. Sometimes, depending on the other ingredients in the paste, oil can be helpful for blending (but so can water or other liquid(s)). It need not be flavored oil; it becomes flavored during the process. Use less than you'd think.
Because I want the depth, I make a rub as usual for the pre-cook rub. If adding an end-of-cook rub I use only the elements in that rub I want to bring to the fore. This (for me) means I do not include chilies (with the possible exceptions of Aleppo or aji amarillo or mirasol), nor herbs; nor much, if any, sugar, the aromatics garlic, onion and ginger, or the more distinctive spices or the ones that already tend to hold their flavor (cardamom, nutmeg or mace, fennel or aniseed, clove). What I do make, if doing this, is a mix of some of the others and apply it very lightly. Elements here might include cinnamon, allspice, coriander, sumac, mahlab, the various peppercorns (ground), powdered citrus zest, grains of paradise, Aleppo, cubeb, coffee bean. There are exceptions. I will sometimes add herbs (usually thyme, marjoram, basil and/or sage) for some beef cuts if I am looking for a more herb-y finish. I grind very, very well for mixes used late in cooking and might add a little sugar, salt or innocuous chile (like ancho) if needing to bulk it up for better coverage. Again, I apply very lightly, usually holding my sifter high above the meat's surface to maximize the potential for an even, light spread and minimize potential for heaviness.
Moreso than not (and another thing to consider) I simply include the elements I want to boost (or add) as part of a finishing glaze. Glazes should not be confused with sauces--i.e., the sauces that many apply to their ribs during cooking that tighten during cooking are not, imo, glazes--but a simple combinations of ingredients, first tightened in the pan, that are applied very thinly--painted on, actually--near the end of cooking, are virtually transparent, do not deleteriously affect surface texture, add shine, and add a flavor layer. Flavors one wants to add or boost are easily added this way.
