As long as they don't abandon the construction techniques or baseline selling points of the existing G3/4/5, I don't care about modularity, although if I was in the right place in my phone lifecycle to get a G5, I definitely would have.
LG is the only company making a flagship phone with a removable battery and a card reader. Being able to swap a battery after shooting a lot of photos or video is infinitely better than being tethered to an external battery, and moving cards around has obvious benefits as well.
But the G3/4/5 are also held together with actual screws. You don't have to delaminate any glass. You don't need suction cups or special pry tools to fix one. I can completely field strip one to its components in about 90 seconds. This is a huge selling point, especially after some of the bullshit I've had to do to work on newer Apple and Samsung phones.
As long as the G6 keeps those aspects, it's all good.