Team-Ranked (5v5) matchmaking flawed?

This thread will be discussing ONLY the 5v5 team ranked system. (Just wanted to point this out one more time to avoid mix-ups with plenty of other SoloQ-threads).

First of all: This is not going to be one of those threads where I post a lolnexus screenshot and then start bitching about "only Diamonds in my games". This thread will try to point out actual flaws of the 5v5 Team-Ranked match-making system.

A little history first: we re-started our team at the beginning of this season (S5) and got placed in Bronze-3. That's expected since we are all a bunch of casual players with individual soloQ-ranks from Bronze-1 to Gold-3 and we lost some of our placement-matches. After that, we have been able to climb pretty steadily to Silver-2 with a winrate of about 70%. Now this is where the issues start. From this point on, the groud seems to have tilted quite a bit, making the following games an uphill struggle (metaphor ends here). The games we play now in this devision tend to go one of 3 ways:

1. It's an even matchup, meaning: both teams MMRs (3rd-party sites used) are roughly the same with enemy-teams Solo-Q rank between Bronze-2 and Gold-2. These are the interesting games. We win these most of the time through individual skill and lane-snowballing - sometimes good combos after the 40-minute mark.
2. Enemy team is a smurf-team. Meaning 3-5 of their players are high Gold/Plat/Diamond tier and their team has played not even 10 games. These games are usually stomps on their side, tend to be very unfun and end up in a surr@20/25 when the score is already 3/20+ at that point.
3. (This is propably the point that irks us the most) Enemy team MMR is above ours by quite a bit (1350 vs 1650). Their team usually consists of many players with SoloQ Gold rank with some Platinums in between. In these games we struggle most of the time. After a laning phase which tends not to be all that bad, we start to loose more and more control of the game after that. Or one of our lanes looses hard and the enemy laner starts snowballing the game after that.

These observations are of course not always 100% accurate, but this is the impression we got in the last 2 months. I will now point out my issues with this matchmaking:

• Why does the system think it's OK to match two teams against each other, when one of them has a clearly superior MMR-rating. I know the old argument about Queue-Times, but honestly I would be totally OK with queue-times of up to 10 Minutes if I knew I would get opponents whose Avg-MMR is not 300 (or more) Points above ours but only maybe 100-150. We are justry triyng to climb to Gold-5. We don't have ambitions to become all Challengers. Why do we have to prove our skill against Gold2-Plat1s when all we want is get to S1/G5? What the hell...?!
• At no point should any player on the enemy team have a personal MMR greatly above the average of my team. I mean, come on... what can Silver-X players do against a Diamond-4 player with over 3000 games in his history? This may not be such a great issue at higher ranks (Plat+) but in lower ELO one individual player can snowball the whole game so hard and can single-handedly carry the whole team.
• Shouldn't newly formed teams start at rank that better fits their average-personal MMRs? Making lower ELO-teams get stomped by highly-skilled players who felt like "having some fun" is only fun for one side. This seems a no-brainer to me. Why has nobody at Riot thought of this in four years?

I don't want to sound too whiny here, but it's getting difficult to keep up morale when every time you check the enemy's comps before or after a game you realize that you have been fighting a battle which was already lost at loading screen. I do not mind loosing every other game if I know it was because we made mistakes or the enemy team comp was just better or because of some other reason which originates from the actual gameplay.

Is this just us, or are other teams have similar problems? Are we just having bad luck? I dont' know ...

Some ideas how to solve these issues (I already mentioned some in between):

1. Lower the Average-MMR-range for a matchup to a deviation of a maximum of 150.
2. No team is allowed to Queue-Up if the MMR-"gap" between the "lowest" and the "highest" player is too great. Translated into Rank this would be something like: Example 1: Lowest: Silver-5, Highest: Diamond-4 = NOT OK Example 2: Lowest: Gold-5, Highest: Gold-2 = OK
3. Implement a system which prevents newly formed teams to start in Low-ELO (< Gold-3) if average-MMR of all individual players indicate an already very skilled team.