All depends on the person of course. Maybe many folks starting out today would love the techo-capable SeeStar smart telescope. But "generally" a 4", inexpensive, achromatic refractor on a simple to use alt/az mount is pretty bulletproof.
The combination of ease of use, no maintenance, sharp images, enough light gathering for the showpiece deep sky objects and even the ability to do solar observing is a combination that will nurture a budding interest.
For a beginner, ease of use and instant results are more important than aperture or expensive apo optics. Heck, many old-timers here have 4" refractors exactly because of those attributes.
Bob
It really does depend on the individual. That's why I make no generic suggestions and try to help the beginner make an informed decision rather than recommend something.
That said, affordable, entry level 4 inch refractors generally have flaky mounts that are not so easy to use and are prone to vibration.
Optically, you have to choose between a narrow Field with moderate chromatic aberration or a wide field with rather severe chromatic aberration that is not at all sharp at higher magnifications.
A 4 inch refractor does OK under dark skies on some objects, it's disappointing on others. Setting up next to an 8 inch Dob is not recommended.
I began with a long focal length 60 mm refractor with no finder, one two element eyepiece lashed to a photo tripod.
I own two 4 inch APO refractors, both bought used. Either one, bare bones, no mount, no diagonal cost more than an 8 inch Dob. What you describe is not an entry level 4 inch refractor, it's morecsimilar to a quality APO/ED on an expensive mount that will still be outperformed by an 8 inch Dob.
I just have away a pair of 4 inch refractors, one is F/6.5, the other F/10. The mount was a bit undersized, a Twilight 1 but it was riding on a heavy duty tripod with 2 inch Stainless Steel legs. That's hardly a typical entry level 4 inch refractor but hopefully it will serve the new owner well.
A 6 inch F/8 Dob would show more, be easy to collimate and cool quickly but I didn't have one...
I think this pair of 4 inch refractors is a good fit for this particular friend but he would appreciate just about anything.
I can make a sales pitch for a 4 inch achromat but you did that. I wanted to add some balance.
For an 8 or 10 inch Dob, I don't see collimation and thermal acclimation as the most serious concerns, even out of collimation and not cooled down the views can be quite decent. These are concerns but doable for most.
I'm more concerned about the physical size, these are big scopes and for many may present difficulties just lifting the scope. Some years ago, I was loaning out my 10 inch Dob to a friend and the OTA was just too big and heavy for him..
Our role is not as salesman for our favorite scopes but as friends and mentors, teachers. Why are you interested, what do hope to see? How dark are your skies. Are you a hands in person or someone who prefers not to mess with gear? How strong are you? How big is your car? Etc, etc
Jon