I guess the more important question - and one I've never seen addressed - is WHY the show runners decided NOT to have a main character serve as Chief Engineer at the beginning of the series???
The same reason they didn't have a chief science officer or a communications officer or separate helm and navigation officers, and why they had an operations manager, a counselor, and a regular security chief when TOS didn't. One, they didn't want to copy what TOS had already done, but wanted to try a different, fresh dynamic. Two, they wanted to show that technology had advanced to the point that the ship could pretty much take care of itself and you didn't need as many people to handle its functions. The original TNG bible called it "Technology Unchained," the idea that technology had become so autonomous that humans were freed from drudge work and could devote themselves to intellectual or artistic pursuits with technology supporting their endeavors.
But as the season went on, they realized that a lot of the episodes needed someone in the engineer role to give exposition about what was going wrong with the ship and so forth, so in season 2 they decided to have a regular chief engineer after all.
Worf was characterized as being kind of dumb at first so he wasn't going to be engineer.
Young, impulsive, and having a lot to learn, sure, but nobody "dumb" gets to be a Starfleet officer. Worf was defined as a new-fledged command-track officer gaining experience through his watch-officer post, and expected by Picard to "learn, learn, learn" ("Lonely Among Us"). It was implicit that he would grow and learn over time. And really, a generalist like season 1 Worf would've been a more plausible candidate for a permanent engineering posting than a flight control specialist like Geordi.
Although if we're talking about alternate character positioning, maybe have Yar be a hotshot pilot and have Geordi and Worf in their regular positions to start with. Her sitting next to Data up front would have also given them opportunity to build that relationship a bit more. Maybe Crosby never leaves the show in this instance with everyone having a clearly defined role to start with.
I don't see that happening, since Yar (originally "Macha" Hernandez) was modeled on Vasquez from Aliens. So being the resident fighter was the foundation of her character.