The only issue with the battery door is people not making sure it's locked and it clicks. If you do, it won't open accidentally. Ever.
Not so. The battery compartment on the G30 and G50 transmitters are very tight, and don't make allowance for the fact that many rechargeable batteries are slightly oversize. This has apparently been corrected with the new transmitter for the G55.
There are LOTS of references to battery door problems with the G30 posted here and on the Line 6 forum. Most seem to be by people who use rechargeables. The usual end result is a broken latch, and various kluges using Velcro, or a strip of bicycle inner tube. Based on the aggregate experience of all those users, it's best to stick to alkaline or low-capacity Duracell rechargeable batteries with the G30.
Whether that matters to the OP, depends on his feelings about non-rechargeable batteries.
There are also references to problems with the plastic jack in the G30. I imagine that's more likely to be because of the jack wearing out, than the fact that it doesn't lock. Ditto with the jacks on all but the latest G50's, which had plastic internals inside a metal collar. Lots of frustration and warranty claims over that issue.
That said, if I hadn't had the $$$ for the digital Shure, I probably would have sprung for the G30. Like you, I'm easy on my gear, so the plastic content of the G30 transmitter never scared me.