Ranked 5s and unbalanced teams

I already contacted Riot support, but they told me to post this here. Originally a posted team names and summoner names, but I left that out. Here is the edited version of my email.

In my 5v5 team each of us have similar solo queue rankings. We are made up of 4 gold players and 1 silver player. Last night we played a 5v5 team that was made up of players with vastly different solo queue rankings--1 silver player, 1 gold player, 1 bronze player, and 2 platinum players! The 2 plat players wrecked our team and ruined the enjoyment of ranked 5s. As you know, there is a hefty skill gap between plat and low gold/silver. Why should my team, with low gold solo queue players, have to play a team with plat solo queue players?

This wouldn't be such a concern of mine if this was a one off occurrence, but it happens often enough. I even remember going against a team with a diamond player.

In solo queue, a player can't duo queue with another player a tier above or below. I assume this is to prevent a large skill gap (a diamond player and a bronze player duo queued would make matchmaking difficult, and it would be unfair for a diamond player to play against bronze players and vice versa). But if it's not possible in duo queue, then why is it possible in ranked 5s?

I enjoy this game because matchmaking places you with and against players of similar skill. But ranked 5s is a crapshoot. Sometimes you go against players of equal skill, and sometimes you go against players tiers ahead of you. That's not fun!