My biggest problem with any of the magazines is the need they have to sell tackle. They exist more it seems for advertising revenue than the money made from the sales/ subscriptions... (and I can understand how that must be the case). However, what it does then mean is that all of the tackle reviews you ever read are totally glowing, which just doesn't seem right to me. I'm sure that on a number of occasions, the guy in charge of tackle reviews has taken a reel or rod for a test and thought "how on earth can I polish this turd...." because ultimately that's what he'll have to do (to keep the manufacturer sweet and the advertising revenue flowing....)
Also, when you think about fishing in itself, it's a pretty straightforward kind of activity. The "amazing new developments" in any discipline are there to drive tackle sales rather than catch rates. A couple of bits of sweetcorn on a size 8 fished under a waggler with 10lb line straight through will still catch you a massive carp (if you do it right) but that won't put a penny in the Korda pension pot will it?
Having said all of that - for most anglers - there will always be something "new to them" which the mags might lead you to. I've never caught a pike with a surface lure; I've never caught anything on a fly; I've never caught a zander; I've never fishing in a "proper" match; I've never caught a salmon; I've never used a marker float/ spod set-up; I've never "bivvied-up" for a session; so despite over 30 years of multi-discipline angling, there's still some new things for me to try!