I WAS an engineer for a while designing nylon threshers and injection molding machines... and both my father and grandfather were millwrights in the rope making industry... In addition to my old man being a gunsmith. I think that is a good deal of the difference in mindset... the designer is usually only concerned with how pretty it is -- the engineer is thinking maintainability, sustainability, accessibility, ease of use, and all the other important things... and when the engineer says "no, you can't do that", LISTEN!
When you let the "designer" dictate things, that's how you get buildings shaped like a parabolic dish cooking people in the office next-doors, waste resources putting balconies where there's no window or doors, or spend 11 years struggling to make a measly (by modern standards) 1300 foot tall building that ends up the most expensive in the world -- scary when it's already taking twice as long and costs twice the Burj Dubai, Shanghai WFC, or Taipai 101.
Oh wait, aren't two of those the same "designer"?
Well, kinda OT..
Reminds me of when I was a teen and they were building us a new high school to split the town in half. Instead of bringing in the contractor who did five new middle schools in ten years far, far under budget, they took the advice of 'forward thinkers' on said buildings being too utilitarian and uninspired... and brought in some foo-foo frilly designer...
Who then proceeded to make a building where every door opened inward, had no fire extinguishers in the tech wing or cooking classes but placed 5 of them in the band room (got to worry about all that brass catching fire), had a 'bricko' wall in the gym and cafetorium just to be sure the bullies had something to smear the underclassmen against... oh yeah, a 'cafetorium' because the acoustics of a cafeteria are great for performances and a carpet is so great for keeping clean in a high school lunch-room, a flat roof that collapsed under the first snowfall since the 'designer' didn't want obvious drain pipes so there was no-place for rain much less snow to go... but the piece de resistance?
The floor of the entranceway to the 2nd floor library, with 2" diameter holes in the walkway into it to allow light down to the room below -- which was the main entrance to the building. So of course any crud that was on people's shoes upstairs would fall on anyone walking in... much less god forbid someone on crutches tried to enter the library... so they fit glass inserts into the holes, that acted as magnifying glasses making burn marks in the carpet AND magnifying the view up girls skirts.... so they went over the glass with a sander to rough them up and with a stain to reduce the light passed through -- leaving no illumination in the entranceway. Naturally since it was supposed to get light from upstairs, they dind't run conduit to add electric lights inside the SOLID walls, so they just strung extension cords and clamp-lamps in since by that point there was no money left to do anything proper about it.
Then of course it needed to be painted overpass green as a 1 foot stripe around the roofline, hot neon magenta walls inside and out, and of course yellow trim... on steel frame windows so the paint was already flaking off six months after construction.
Net result was a building that cost three times the plan and STILL wasn't useful as a school. I was struggling to figure out how we were even allowed in the door given the endless fire code violations -- since last I knew they never even fixed the doors! You'd almost think it was the Commiewealth of Taxachusetts or something -- where public safety laws don't apply to government agencies or if you just wave a bit of cash under the inspectors nose. Now I'm not saying corruption is rampant... Oh wait, that's EXACTLY what I'm saying... There's a reason I moved to New Hampshire.
Designers -- BAH. Again, it doesn't matter how pretty the result is, if it's useless, what good is it? Most "designers" need to stick to paper, as they lack the practical knowledge to make sound choices, then expect the engineer to work miracles out of their noodle-doodle impractical and often disastrously bad thinking.
Were that most designers had practical working knowledge of what they were designing for -- like Chip Foose does. Until you have the knowledge and experience to build it, IMHO you have zero business "designing" a blasted thing! Hence why I say that sitting around drawing pretty pictures in your paint program of choice is NOT "web design", it's a pointless time waster that results in broken impractical sites built from unrealistic expectations.
"But I can do it in Photoshop!" -- <cosby>Right...</cosby>
Again, as I've said several dozen times, there's a reason you don't see the PSD jockey designs on any of the real success stories of the Internet, and instead see them on personal websites, game websites that are so useless people don't even bother visiting them (call in the flashtards), brick and mortar businesses for whom the Internet is a afterthought, and small businesses who got swindled using the classic "ooh shiny" predation.