@ThunderDeliverer given your two overloaded methods, would it make sense to either require or recommend the following implementation:
isTransferable (uint256 tokenId, address from, address to) {
return isTransferable(tokenId) && fromToBasedConditions;
}
By the way, we just did the PR for the EIP I mentioned earlier (discussion in Draft ERC xxxx: Asset-Bound Non-Fungible Tokens), I already referenced this ERC there and will adapt our draft accordingly, as soon as this is becomes a final EIP.
Of course, happy to receive (critical) comments on our proposal.