TLDR: Small Creeks don't need a small rod.
I'll be that guy, why a small rod? I use a 9' 6" rod all through the late 80s and 90s in the tiniest of streams. I now use 10' and 11' rods almost exclusively in 2 wt and 4 wt.
I never have seen a need for a tiny rod that
- won't cast far and makes casting issues
- a pain to mend line
- isn't great for keeping the line tight when fishing
- seems like a good idea but fails in practice
Bigger rod you just need to learn how to control the back cast or just get creative. 2 weeks ago a friend couldn't get his nymph under a tree branch. The casting space was tiny, brush on my back and head and couldn't move to the left. After about 10 attemps I got it right there and caught the biggest fish in that river, but it wouldn't have happened with a smaller rod.
My Two Cents.
I always prefer the longest rod I can get away with but I fish some creeks that are so hemmed with rhododendron that just walking INTO the creek is almost impossible. The creek pictured below is one example...
I fished it with 6'6" 3wt and had a miserable time trying to move around and get a fly in the water. Casting in more than a few spots consisted of grabbing a handful of line along with my leader & fly and tossing it into an opening for a downstream drift.
That's something that would have been a real challenge to pull off while standing further back with a longer rod. Aerializing line over this creek, impossible...
When I got home, I ordered a 5'0" 3wt which made life a WHOLE lot better at that stream and a few others...
I also fish a couple of very small wild trout streams with excellent fishing and relatively open water EXCEPT there are some REALLY low bridges with deep holes below and just above that hold LOTS of fish. The best and only way to effectively fish those spots and get good drifts without spooking all the fish is to wade upstream to and under the bridges.
While standing underneath those bridges with a 6'6" rod I can cast side arm, set the hook and land the fish by stripping in my line because there really isn't enough space to hold the rod upright. While standing UNDER one bridge in particular, I've had many days when I caught 6 or more wild browns by making short casts to the spots under and just above the bridge.
Other than a couple of casts shot up from the downstream side which might result in a fish or two, you couldn't effectively fish that particular spot with a rod longer 7'6" because there just isn't enough room under there to cast or even move a longer rod.
You also can't fish the short stretch just above the bridge where I can always mange 3 or 4 fish because it is all hemmed in on both banks with brush. The only way to access that spot without wading under the bridge is to bushwhack through the brush and step into the creek above the bridge which will spook all the fish...
FWIW - On these short rods are reels which in my case are mostly Hardy or a CFO or two. Obviously pricier than needed but lighter as well and when you fish a rod that short, heavier reels feel extremely clunky.
