I'm completing a significant redo of the Npgsql Visual Studio DDEX provider. Key features are:

• Modern, standard VSIX architecture with a vsixmanifest.
• Completely standard, self-contained VSIX installation - no GAC installation, no machines.config tweaks.
  • Much better experience installation experience
  • List the Npgsql VSIX in the Visual Studio gallery
  • Eliminate lots of issues people had with an incorrect/mismatched GAC installation.
  • This can be done by including Npgsql.dll in the VSIX, and by programmatically adding Npgsql's provider factory as described here.
• Support for VS 2017, with manifest V3 and the light-weight installation.
• Customized UI control for connecting to PostgreSQL, just like SQL Server and Oracle have. No need to go into the property grid with all the possible parameters, just enter the basic (host, database, user, password).
• Clean up the advanced, property grid-based panel where all the connection string options are shown (i.e. remove stuff that shouldn't be there), plus some other VS tweaks.
• Extension should simply build with the VS SDK (or with the Microsoft.VSSDK.BuildTools nuget). No longer include any VS build tools in the Npgsql repository.
• Target multiple modern versions of VS (2015, 2017) without any extra work (simply listing them in the vsixmanifest)
• Evolve the Server Explorer view (view by type or by schema, etc.)
• Automatically version the VSIX with Npgsql, and build the VSIX on the build server. This will eliminate the manual work previously needed to release new versions.
• Resolve various issues (e.g. parameter placeholders weren't defined so inserting data was impossible)

@kenjiuno - you'll probably be interested in all this.