Ghostscript is licensed as AGPL-3+. That's nice. AGPL is arguably a good license for applications, to avoid a loophole in licensing when used in cloud services. AGPL is quite problematic for other things, however, including libraries and fonts. This post (and surrounding thread) explains in my opinon well the situation: https://lists.debian.org/debian-devel/2013/07/msg00317.html
Given that we specifically chose GPL and then AGPL to protect against commercial uses of "GPL Ghostscript", changing the functional core to LGPL is unlikely to considered. I'd also argue that giving one of the reasons for wanting this is because users don't want to share security patches is unlikely to further your case.