A post on Battle.net has more follow-up on placement matches in Heroes of the Storm following a recent comment from Blizzard saying they would investigate complaints of irregularities. They describe reasons they feel this may not have worked so well at the top and bottom ends of the scale, but it sounds like the ways they plan to improve this will apply to the beginning of the MOBA's first season. Here's a bit:

With our most recent patch, we reset everyone’s Hero and Team League rankings and implemented a placement system, which requires that all players complete a minimum of 20 ranked games before they are placed into the ranking system.

After reviewing internal data, we’ve found that the majority of players are being ranked much more accurately. However, we have identified some cases where this was not always true. Specifically, we want to make improvements to the top and bottom ends of the ranking spectrum. In addition, we’ve seen a lot of discussion and feedback about the new system over the past few days, and we’d like to clear up some things about placement matches, ranks, and our plans moving forward.