The prettiest pen, in my taste, I've seen posted here was a Swan Blackbird...........so second tier don't have to be ugly.
I'm really glad you you are into Vintage pens.
Back before I developed the term 'Easy Full Flex' pens were often described as 'flexi', which could have been semi-flex, maxi-semi-flex or first stage of superflex, Easy Full Flex.
Wet Noodle was not a problem in definition.
I'd chased Swan so very slowly, in the six weeks I didn't win a single pen. I'd finally decided to buy it from a professional, for a bit more money....from a restored pen who the seller knew what flex the nib had. Had decided if I didn't, I'd be buying the '50-55 Swan Torpedo sac pen, in the convoluted ways Swan tried to get around patents made for difficult repairs.The last of the Great Swan pens before the ball point killed it off....after '55 the Swan wasn't as good as early '50's.
I ran into a Degussa nibbed 'no name' German War pen, that was the 'flexi' I'd been looking for....Easy Full Flex, so I stopped looking for Swans....never got one.
I had a very nice Easy Full Flex/'flexi' English Wyvern, that I swapped for a Osmia with a Supra nib.
My flex rating system. First you have to have a regular flex nibbed pen. Esterbrook, Pel 200, some Sheaffers, Wearever. I really don't know US pens more than when I had them as a child....do don't know which Sheaffers are regular flex.
Mash the regular flex nib so the tines go 3 X a light down stroke.
Semi-flex takes half that pressure.
Maxi-semi-flex half of that or 1/4th the pressure needed to mash a regular flex to 3X.
Those are the 3 X flex set.
Superflex is 4, often 5-6 and very seldom when not sprung 7 X tine spread. The more superflex pens one has the more variation. But the 'system' works well for superflex noobies.
Easy Full Flex, takes half the pressure needed to make a maxi go 3 X, or 1/8th of a well mashed regular flex.
Wet Noodle....... half of that or 1/16th the pressure needed to well mash a regular flex.
IMO does not need to be lack of spring back as one poster said......
Weak Kneed Wet Noodle...= even less...a term invented by John Sowoba(sp)/Oxnard on the com, a well known nib grinder. Don't have, don't want. I'd really have to learn to write if I got one.
There are dip pens like the Hunt 99-100-101, that make a Wet Noodle look uncooked for flex.
There are many medium flex dip pens that have the ease of a wet noodle and easily go more than 7 X.