When I first wrote God Games,I intended it to be 7 story arcs. The first one being an introduction to the world and core characters and themes. The following four would see the characters setting out and completing their goals. The sixth would be the great character change for the main character. And the final would have been a war arc.
Once again the potential pitfall (or was in God Games case.) is that webcomics take SO MUCH TIME TO COMPLETE.
I envy the reserves manga artist have to write this shit week after week after week after week.
I planned on finishing God Games in 2 years XD XD XD XD. Oda has been writing One Piece since I was born and he AINT EVEN 70 PERCENT DONE.
Not sure why this couldn't be in the other thread, since it seems pretty on-topic there, but...
My take is that if you frame the story like "here are my 7 story arcs, read em' like that or else" you run into the risks of 1. it being difficult for readers to jump in later, and 2. it being difficult to bail out early if you can't finish writing every arc.
Let's look at the poster child for shonen manga/anime, Dragon Ball. Dragon Ball currently has 15 major story arcs, not including GT. However, most people I know (i.e. Americans) only started keeping up with Dragon Ball at the seventh arc (i.e. once the series started getting dubbed). There are also fans of the series who only got into it with Super, and I've even heard of people starting with the Tien arc because that's a part they heard was good.
As for the other pitfall (and the one you're more directly referring to) - Toriyama could have ended the story after Buu, he could have ended it after Cell, he could have ended it after Piccolo Jr, he could have ended it after Pilaf, and while the Tournament of Power claims to be the end for now I seriously doubt that. Sure, there would have been plot threads seemingly dropped (Roshi asking Goku to train with him in the Pilaf arc, for example), and character arcs left unfinished, but there's been plenty of outs throughout the series if Toriyama was ever going to retire permanently.
(though these days even retiring wouldn't end it, because Toyotaro is obviously going to take over once that happens, but that's not really relevant to the thread's topic)
This isn't me telling you to go episodic, but story arcs should be able to stand on their own. There can be foreshadowing and callbacks, but your story should be modular enough where you can write an early ending without worrying about the major themes being thrown under the bus.
Also, if you plan on writing a long form story... do the math for your time estimates. For your own sake. Even at 2 pages a week, 7 arcs in 2 years is only 30 pages per major story arc. I seriously doubt that's what you were planning on for God Games.
Toriyama only got through 3 story arcs in his first two years, and the first 2 arcs ended up being the shortest in the entire series.
For the curious - my plan with Super Galaxy Knights Deluxe R is for each book (except the finale) to have something that Mizuki gains overall, but also show something that she still doesn't have yet. i.e. Book 1 she gained her magic powers and two new friends, but she doesn't have a romantic relationship like she wanted. That way, the series can end any book before 5 if I ever do get tired of creating this, and I'd just have to write the ending to be more bittersweet instead of looking forward to the next thing (though ending after Book 2 would be a bit weird admittedly, since this book has the least tangible things gained/things missing). And who knows, maybe by Book 5 I'll think of ideas to continue the series.
I'm maybe not great at all the terminology and often think about it in terms (for comics) as Overall Story --> split into story arcs/chapters --> Split into parts/issues. So when you say episodes, I'm not 100% sure what you mean but take it you're referring to what I call arcs/chapters as in a self-contained story within the overall story/World.
I agree with SnuffySam in that I think it's important for arcs to be able to stand on their own. Story structure is very important to a well told narrative. Honestly, I think tv shows like Buffy The Vampire Slayer has a good model for this where they split it up similarly. Each episode is a self-contained story with a beginning and an end. They're also part of a season that usually features a "seasonal villain" or threat if you will. The whole thing is part of her story though that spans the entire series.
What I like so much about this model is that it lets you play around a bit with the narrative. One episode can focus on a specific plot, mystery and/or conflict. But during these episodes have all or some of the characters interact and threads from the season are interwoven into the standalone arc and drive that forward at the same time. Whedon has described that he wanted each season to have a natural ending Point where the show could have ended. The only exception being season 6. This is in my opinion a smart way of telling stories like the one I imagine you're shooting for.
Obligatory example of own work:
The above is exactly how I've structured my comic Voidchild. There's a "season" that has a natural ending Point which should provide a satisfactory ending to the series if need be. It's split into separate arcs/chapters that tell their own contained stories. These are split into parts or "issues" which are 22 pages each. I think of the issues as that part in a tv show where it goes to Commercials and there's a bit of a cliffhanger to keep you coming back (if I've done it right).
I've personally found that setting a framework or restrictions for myself has helped (read "forced") me to think more about the contents of my series. I won't go outside the 22 page issue format for this reason because I know I could and would probably spiral away and fill it with unncessesary fluff. It forces me to be more concise and get to the point (again, when I get it right).
Back to your question:
I haven't read your comic, so I can't say if you should try a different model beause maybe the one you have works for you. The above one that I describd and use myself is my preference for the reasons I've outlined. It's also the ones I prefer to read/watch myself for what that's worth. =)
My story arc situation is complicated.
At first, there were no story arcs, simple gag-a-day strips. Then a serious strip evolved to be the first story arc, affecting further gag-a-day strips. Then a short light-hearted, also free of continuity. And now I initiated a retcon with more story-based arcs. As of now, they're pretty self-contained, though certain details hint continuity. However, I play them to be more connected with each other, though still including short "breather" arcs.
So far everything's going according to plan... Though it ain't bringing me any subscribers, still.