Ehm no. I think it's more like people are stepping outside the bounderies of the elements when making custom jutsu's and less like that CE are starting to take away the properties of the elements =/
First and for all making a custom element is something almost symbolic. You can't be called a true RPer if you haven't made your own CE. Whether people have this feeling consciously or subconsciously I don't know, but it's a fact that CE have a certain attraction to people. Originally the CE started with reasonable normal things, however the number of RPers increases and "normal" CE aren't unlimited. The result if this was something that could have been predicted from the moment CE came into existence as it's a logical consequence. So people start searching more and more detailed.
Does that make their elements any less a real CE? No, then you don't understand the elements you use. If you say fire is fire and water is water you absolutely don't know anything at all about the elements =/
I certainly wouldn't say that all the elements are true elements. There are some where I too have my doubts about, however most of them can still be concidered real CE.
Blue fire, white fire, sun fire...yes they can all be placed in the category of "fire". However a lot of people in this thread are actually at the point of seeing them all as one and the same, then you're just being ignorant because that's the same as saying that all humans are the same, that everyone could run as fast as Usain Bolt or swim as fast as Micheal Phelps or dribble like Lionl Messi as they are all "humans". They are all considered fire because they share some identical aspects, but they aren't the same as there are still a lot of differences too. Sun Fire is made completely different than normal fire, blue and white fire have completely different aspects too. The proof is in the manga: everyone uses normal fire, never blue or white as they're different. Another thing I need to add to this is that Amaterasu is also fire, still no one is complaining about it, no one has trouble seeing it as something completely different. You need an MS to create it, just like you need for Sun fire etc. specific requirements, which makes it a CE.
Same goes for metal. You can go check all the metals in the Periodic Table and say that they are all metals, but there are still differences between them. Some are extremely flexible, others are very heat-resistant etc.
Also by saying
"if I did it using only one element, how can there be a CE of that" you're indirectly implying that everyone who knows water and earth can create wood and everyone that knows water and wind can create ice. Yes that's what you're actually saying as you say that because you know a specific element you should be able to use it at its uttermost limits, in the case that you would know wind and water so well, it should be easy for a lot of people just to create ice.
I won't deny that there are some "odd" CE, however around 90% or more are good. As I mentioned before it's more like people are stepping outside the bounderies of the elements when making custom jutsu's and less like that CE are starting to take away the properties of the elements. In the manga lightning is pretty much shooting lightningblasts or things along those lines. When you start using lightning in such a way it isn't actual lightning anymore you can call it a CE, even if it's only based on one element. For example Kirabi had once a lightning custom with which he used lightning to start messing with ions so that he could transform one element into another. In theory that's possible, however do you still call that lightning? No, it was just another variation of the Radioactivity-CE.
I don't know what your custom was, though people have the urge for searching more and more original customs, which results in people starting use the elements in completely different ways that they're actually making CE and often come into the territory of already existing CE. Who's then in fault? Probably both, though saying what you're saying is just complete wrong.
And I'm completely against treating CE as KG =/ One it's not true as Shodaime made wood which wasn't a KG. I know there's a difference between a KG and treating like a KG, but the concequences are completely messed up. Do you even know as to what the would result? Every bio should be rechecked as a lot of bio's would suddenly be breaking the rules. Not to mention that the older members, who have the CE, would see things they build up for months instantly crumble and new members would never be able to use it like them. Who's going to be happy? This would lead to an unorganized mess.
Not to mention for what? What good would it do?
When people specify in certain techniques/elements, it's logical that they would make a CE of it or something, just like the Shodaime made wood. Every CE needs to have strengths and weaknesses, otherwise they won't be approved. So I see no reason to start treating them like KG.
Personally there are some suspicious CE and some odd cases, however most of them are OK and nothing should be changed. I find this almost a case of "changing evil be evil". If you would take away some CE based on one element you may kill that threat, but than you create the threat of people making extreme ridiculous jutsu's. I find this thread nearly as pointless as the one of the OP jutsu's.
PS: I would advise some people to keep a low profile. The RP-system is almost like an organic system, it has evolved over time, both in good and bad ways and the result of this is that you just can't instantly start making any changes as the base remains the same. Some people should realize that they're the ones who created that base and are now complaining about it

They are some people who really can't appreciate this kind of behavior, especially as I mentioned the RP-system always evolves and that in the past you maybe knew it well, but that doesn't mean you do it now. That has been proven with the extremely pointless discussion about OP-jutsu's.