I think one can make it as complicated, or as simple, as one wants it to be. Who says you CAN'T spider rig with poles less than 10ft long, shoot docks with poles longer than 5ft, troll with only one or two poles, or vertical jig with a short rod ???
I can tell you this ... I've done exactly those very things, and I've had success doing it. Could I have had "more" success, had I used what the majority of people suggest I use for those techniques ?? Who knows ... and better yet, what does it matter ? I'm fishing for pleasure & to put a few fish on the table ... not tournament fishing for fame & fortune.
I have two outfits that are remotely the same (ie - same rod/different reel) ... and I never take both of them at the same time. I generally take no more than 5 outfits with me, and only rarely do I use more than 3 of them (either at the same time or during the course of the day). I have exactly 20 outfits to choose from, that are all dedicated Crappie fishing outfits. I choose which 5 I'm most likely to use, based on the lake I'm going to, and the probable location of the fish (as the season & water conditions dictate). If I have recent, trustworthy reports on what the fish are doing, where they're locating (type of cover, & depth), and what techniques are being used to catch them ... I'll rethink what outfits I'll take, and utilize those techniques (if I'm equipped to do so) or simply disregard the techniques & focus on using whatever technique I can to present my bait at the proper depth & speed.
If I wanted to downsize my arsenal, to say three outfits that would cover most of the techniques that I'm likely to use ... I'd have a 6ft, 7ft, & 8ft spinning rod. All three could be used for most minnow or jig use (tightline, trolling, casting) ... & the 6ft rod would cover my dock shooting, while the 8ft rod would cover any vertical jigging I might do.
There's no law that says only one technique will work at any given time, and there's no law that says each technique has to have its own series of rods/reels, and there's no law that says you have to know every technique in the book (or use them) to catch Crappie. Many are the times I've been fishing & using one technique with success, while watching others use a different technique with the same success. Our equipment couldn't be the main factor, our baits were different, our knowledge level was likely different, and we weren't even fishing the same type of cover .... so that only leaves one thing in common -- we were presenting our baits at the proper depth & speed, under the prevailing conditions. With that in mind ... if I were to remove dock shooting from my technique list, or revert back to how I fished before I even knew about dock shooting ... I'd likely have 3-5 outfits in the 7-8ft lengths, and be casting/trolling/tightlining the same way I did back then.
I have 4rod rod holders on my boat, but never have more than 3 rods in them. None of those rods are over 10ft in length, and never do I have any of those 3 rods the same length. I don't "spider rig" out in front of the trolling motor ... I do it off to the side of the bow, with a rod spread angled towards the front & side. My backseat partner has the same situation. We've had success doing it this way, all the same. When I fish with other buddies of mine, from the backseat of their boat, and they have rod holders ... I still use the same outfits I'd be using if fishing from my boat, and I still catch my share of the fish. And that's while fishing behind a guy using 4 or 5 fourteen to sixteen foot poles, controlling the direction & speed of the boat. But, I'm not there to compete with him, but to be a "partner" in his quest. It also helps me understand the frustration that may come with being a backseater, so that I make adjustments to help give my backseat buddies a fair shot at catching fish when they're in my boat.
... cp