There are two things I will always have in my tool chest:
1. A high quality, properly calibrated set of torque wrenches in any drive type and torque level I need.
2. Manufacturer spec'd crimp tools for any critical connector I am going to build.
There are connectors on the H-D bikes that allow a little bit of "slop" (Deutsch) and connectors that require "precison" crimps (Molex MX150). In the end if you are comfy with the connection then use whatever method works for you. If you have issues later on, then those connectors would be the first place I would look.

The issue, of course, is ROI. If you "just need that one connector done" it makes no sense to buy the right tool for the job. That's when you hope you can trust your Dealer or an Independent to do it right (he hopefully bought the proper tools). Look at it this way - if you wanted to attach a couple of 2x4's for a project, would you buy an air-driven Paslode framing nailer? Probably not. If you were framing a house then it would be your FIRST purchase

. Or - that's why and when you contract a Framer.
Although expensive (usually) - crimp tools spec'd by the Manufacturer of the connectors are the best choice.
Done once ... done right.
I mean ... would you "guess" the torque value of your head bolts? Rear axle? Front axle? In my opinion, not using OEM crimp tools on critical electrical crimps are in the same vein - it's a "guess" that the signal level will not be compromised and that it will hold up over time, exposure, and vibration.
Face it ... we live in the age of expanding technology. With composite materials for engine components, forged aluminum castings, high-speed data busses for ABS, ECM, Suspension control, and multimedia (Infotainment) out the wazoo - gone are the days of "wire-twisting" and electrical tape. Gone are the days of "it's good and tight". When I do critical mechanical work; I check torque values like fiend. When I (have to) solder wires, I file them to keep signal loss to a minimum and to ensure as little cross-talk to adjacent wires as possible. Unfortunatley ... it will only get worse (from a torque and electrical precision perspective) in the future.
Just sayin ...