If given more choices, it is hard to say no to any bonuses.
If I was asked for ideal functions:
I personally would like regular Pendulum specifics (Scales and text box), regular Link specifics (Rating and pointers), and have the rest be:
-Skin colors for the bases including the existing and potentially existing ones (Normal, Effect, Ritual, Fusion, Synchro, Xyz, Link, Token, Dark Synchro) but go over to include other colors for potential custom made mechanics by members.
-Skin colors for the stars' interior and exterior in a way that people could make negative Levels, regular Levels, or Ranks, and just like the above, go a little bit beyond for a couple nameless skins for potential custom mechanics.
-Orientation for the stars (starts from left or from right).
-Possibility for printed 0 stars.
Buuuuut that sounds like too much work honestly xD
So let's get down to answering the thread...
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I think Link Pendulums would function like Link Xyzs already do. They wouldn't be inherently able to be Pendulum Summoned but they'd still have the "goes to Extra Deck face-up" and/or "if killed, it can become a Scale" properties. Other than that people would have the option of a clause along the lines of, for example let's say a Link 3: "You can Pendulum Summon this card if you can Pendulum Summon Level 3 monsters".
If we are talking about aesthetics, I suggest the pointers go around all text boxes (not just the image box) since Pendulum boxes tend to weld all of them together anyways, and their placing wouldn't necessarily bother other data like code numbers, edition, set number, or copyright. Or at least, they'd look awkward in-between Pendulum Effect and image, when the Pendulum images usually continue on behind the ever-so-slightly transparent Pendulum Effect box.
Tokens would be fun to have, and Dark Synchros brings back memories.