With new Swift SDKs for Wasm there's no need anymore to maintain a set of custom options and linker invocations. Custom allocators, RNG implementation, or custom imported functions for IO aren't needed either, you get all of this working out of the box with the Embedded Swift SDK for WASI, while low level details are already handled by WASI-libc. By default the standard WASI _start global exported function is used as an entrypoint for top-level code or @main entrypoints, adjusted accordingly if you pass -mexec-model=reactor via unsafeFlags in your Package.swift.
Binary size is not significantly impacted that way, a hello world printer built with Embedded Swift SDK is still under 10 kB. I don't think there's a reason to maintain custom driver and linker invocations, especially if you're writing portable and reusable packages. Otherwise please let me know, I'd be happy to make this as smooth as possible.