After being fired at the end of the third season, the creator of the quirkiest comedy on TV is, to the delight of fans, back in charge. Here's why the show needed him back

It's not easy being a die-hard Community fan, not least because we had to spend much of 2013 refusing to acknowledge its existence on the grounds that Community without creator Dan Harmon at the helm is no sort of Community at all. After Harmon was fired in 2012 at the end of the show's third season, production company Sony and US broadcaster NBC, rather than pulling the plug on the critically acclaimed but perennially low rated show, brought in Moses Port and David Guarascio, best known for the enjoyable but straightforward sitcom Happy Ending, to write the fourth season. For most Community fans this decision was a disaster (or to put it in Community-speak, "It was the darkest timeline"), a halfhearted attempt to do Community that came across as a poor copy of the inventive original.

It wasn't Port and Guarascio's fault. Happy Endings demonstrates they can write a comedy; the problem is they just can't write this particular comedy. As Community's nominal lead Joel McHale said back in January: "The show is in Dan's brain – and he's by far the only person that can do it."

Thankfully tomorrow we can all start to breathe again as Community season five arrives in the UK. Admittedly it's still on the Sony Entertainment channel (and why BBC2 or C4 never came in for it remains one of the great mysteries of our time) but the good news is Harmon's back in charge and it's as though season four never happened. By his own recent admission: "I watched season four once and it was weird." So will Community be back on previous form in season five? Absolutely. Here are five reasons why:

1. Harmon's, er, unique mind

A Hollywood Reporter profile saw Harmon describe himself as a "rude asshole" and there were repeated stories of erratic on-set behaviour before his sacking. But Harmon's mind works like no one else's. Last season's damp squib demonstrated that, at its worst, Community is an uninspiring tale of a mismatched bunch of people creating their own oddball family. In Harmon's hands it's an insane trip through the pop cultural references of the past 40 years, stacking joke upon joke until you're worried that the whole Jenga tower might topple over. Harmon turns it into an epic journey filled with multiple timelines and every possible style of humour. Somehow, it all works.

2. The return of crazy plots

Whether it's Troy and Abed building a Dreamatorium so they can let their imaginations run free or the whole gang playing paintball to save Greendale's very existence, Harmon was a master of making ludicrous plotlines seem like the logical solution. Season four tried to capture some of that spirit of lunacy – the Muppet episode, Intro to Felt Surrogacy, was a particularly valiant attempt – but the jokes never quite worked and too many plots were left dangling. Even at his most self-indulgent, Harmon also has a clear idea of what he's trying to achieve. One of his goals for this season was to "strip down the characters" – he does this by having the now graduated Jeff Winger return to Greendale as a teacher, an idea that refreshes the group dynamic without fatally changing it.

3. New episodes hark back to classic Community

Harmon might claim he's cutting down on in-jokes in season five but many of the episodes refer to previous episodes. Introduction to Teaching sees pop culture-obsessed Abed take a new course called Nicholas Cage: Good or Bad? and slowly morph into the actor. His impersonation is not only very funny but it's a welcome callback to season one's Introduction to Statistics, in which Annie hosts a Day of the Dead party and Abed attends as Batman (prompting Pudi to unleash his hysterically accurate Christian-Bale-as-Batman). This nodding to Community in its prime can only be a good thing.

4. Harmon's characters subvert expectations

One of the main problems with season four was the sense the new head writers didn't really "get" the characters, writing them as stock types rather than real people with quirks. Harmon is a genius at playing with stereotypes. Former football jock Troy (Donald Glover) turned out to be the most sweet-natured member of the group; high achieving Annie (Alison Brie) is both daffy and demented, only ever one A-minus away from total collapse; and maternal Christian mother Shirley (Yvette Nicole Brown) is actually the biggest badass in the group. Even Jeff is lifted out of the ordinary when it transpires he might really be as shallow as he repeatedly claims.

5. We can dream once more of six seasons and a movie again

One of the funniest gags in Community came when Abed expressed his love for superhero drama The Cape, only to have Jeff remark: "The show's gonna last three weeks." Abed's reply, "Six seasons and a movie," was adopted by Community fans as a mantra whenever our beloved show seemed under threat. Although Harmon's departure dimmed the fire somewhat, his return means we are free to dream again.

• Community returns to Sony Entertainment Television on 10 April at 10pm.