I don't really agree with this. Allow me to explain:
If a multi-player party is on my team in Dynamic queue and I'm the "solo player" it makes no difference to me. At the end of the day they are still going to play their expected roles and do their jobs in a similar manner as would a 5 man PUG. The only REAL difference is the possibility of them being in voice comm with one another and thus possibly having better communication with one another in real time. HOWEVER this is not always the case, as playing with my friends has illustrated this time and time again. A lot of people talk shit, dick around, or even get frustrated and argue with one another when the game goes poorly in voice comm, and this lowers the "potential play" of the group significantly. Voice comm, in my mind, is not an innate advantage. Especially at low levels of play where people don't actually know how to play the game and just mindlessly lane phase long after towers fall, or joust down mid lane forcing bad team fights without any regard to macro-level objective based gameplay.
In these situations, it's really up to your individual skill and ability to work with 4 random strangers that determines your ultimate success or failure in game. That sounds a whole lot like solo queue to me.
Now let's look at the flip side of the coin, a large multi-player dynamic party on the enemy team. In my experience (as a low Plat player) the only time I see a large grouped party on the enemy team is if there is one on mine as well, that's how the matchmaking system works, or at least attempts to work. I understand at the higher levels of play this breaks down significantly, this can be seen on many high ELO streams. However let's all be real for a moment shall we? The people posting on the boards are not high ELO players (mostly, there could obviously be exceptions). I would even be willing to make so bold a statement that, as a low plat ranked player, I am in the MINORITY of posters, and most people fall into the Bronze - Gold category. Again, I will reiterate that this is a broad-stroke statement and I could very well be wrong, I am in no way attempting to suggest I have definitive data to support my opinion.
But back to the matter at hand.
If my opinion, for the sake of argument, is correct, that means the vast majority of games played are not being ruined by the random Diamond 5 player getting shit on by Master tier/challenger premades grouping together to reduce queue time. In most cases a dynamic group on the enemy team will be 2 - 4 players of marginally equal skill, matched against a similarly sized party of equivalent skill, with solo queue players added in to round out the teams. This is my understanding of how the system works. The primary issue as far as I can tell is most likely role disparity between the two premade teams, which can most certainly feel like you're getting stomped by a higher-level player if you happen to roll the dice and lose. (especially in the case of bot lane, which is a powder keg already even without jungler intervention). I however believe that this disparity is for the most part blown out of proportion.
The low ELO community seems to be very impressionable about the state of the game, they probably watch a lot of streams and hear high level players talk about how busted Dynamic queue is, and because their hero thinks the system is flawed, any perceived imbalance in their own experience is obviously the same thing. This could not be further from the truth, but the power of expectation and preconception has a nasty habit of overriding reality. In my experiences as a low Plat ELO player, premade groups have never once ruined the quality of a game for me. Not once. The enemy team had never been so much better that defeat was an inevitable conclusion, and it has always been the actions or inaction of myself and my teammates that lead to any defeat we might experience. If the bot lane gets shit on because our duo lane (or the enemy duo lane) has better champion and player synergy, so be it. This can happen even in "true 5 random player solo queue" sometimes two random strangers just GET one another and play together in perfect unison, other times there is no synergy at all and you just flat out lose. This is just one example of many, the same could be said about mid/jungle or top/jungle synergy. Just because people are grouped up and talking DOES NOT MEAN they actually know how to play together well.
I cannot stress this enough.
I understand that this is a very volatile time in League, but no more so than in seasons past, and I urge players to not be sheep and jump on the "I hate dynamic queue bandwagon" simply because you wish to defer responsibility away from yourself. This will not make you a better player, and this will not call Riot to action and magically make them undo every change they have made in order to placate you. Being good at league of legends as a SOLO player is about adaptability and self-reliance. From top lane down to support, no matter what role you play, even with (or against) a 5 man premade the power is ALWAYS in your hands to win the game through concentrated effort and a willingness to play as a team. If you lose then you lose, look to your mistakes and improve upon them. If you win because you get carried by your 4 man premade, thank them for the carry and move on. Solo queue below Diamond arguably hasn't changed at all, the only difference is the name, the amount of random people grouped up together who probably have no synergy together to begin with, and the expectation that brings.
Do not be a sheep, do not fall into the trap of preconception. Be a solo queue player, win by your own power or lose by it.
*I will again reiterate that this is my OPINION and am not forcing anyone to accept it, nor am I attempting to invalidate the thoughts and opinions of others. I am offering my own unique perspective on the situation. No more no less.