Making LoTW easier to use (and manage and maintain) makes more sense, along with better documentation and promotion/incentives to encourage more of these QSL emailers to join the programme. For example, substantially increasing the number and variety of award schemes accepting LoTW confirmations I'm sure would drive up both awareness and use of LoTW.
+ Localizing LoTW's user interface and documentation for additional languages would help.
Although LoTW itself is free to use, I don't think there are any free LoTW-based awards at present. What would it take to add some free 'self-service' entry-level awards, I wonder, generating award PDFs for us to print and frame at our own expense?
+ DXCC awards for the FT-8 and FT-4 modes, for example. The increased sensitivity of these modes has provided first-time HF access to many antenna-limited amateurs, and would serve as an entry point to the ARRL's award families. "Self-service" would keep the costs low for everyone.
+ The web service developed back in 2016 that accepts an ADIF file and generates a report showing which QSOs in that file are confirmed via LoTW (without requiring user credentials) would - if released - enable radio clubs to conduct on-air activities scored by LoTW confirmations. Making access to this API available to local clubs around the world at no charge would likely encourage more ops to participate in LoTW - as the NPOTA, Centennial, and Grid Chase activities all did.