Engineering is entirely optional if you're doing passenger missions in the bubble: 25 LY vs 36LY won't make a huge difference other than how may jumps you'll need and, I guess, if you don't have a fuel scoop whether you'll need to stop to refuel. Excellent side benefit of the FSD engineering is that you use less fuel, though ... so ... yeh ... personally I think the FSD engineering is a no-brainer and you don't have to go crazy and shoot for G5 right off the bat, G3 makes a big difference and you only need common materials for that.
That said ... engineering your ship how you want it is part of the game. Just as buying bigger/better ships and A-rating modules is part of the game. Only difference is that you have to do something different (collect materials, complete unlock challenges) rather than just plain old missions for cash. Personally I see that as a good thing since it is something different and I enjoy planning my engineering as part of my shop builds. Okay, so some of the unlocks are just "go fetch this" or "go mine that" but at least there is a specific goal (unlock the engineer) rather than just chasing the almighty dollar!!