Here's the problem I have with trying to settle these oddball situations in terms of hard rules that are universally applicable - it all gets dorked up when you change the parameters, like WE speed, base size and so on.
Let's assume for the sake of argument that Onyx's "you may never stop on a friendly infantry model is an absolute restriction" position is correct. That has consequences outside of assaults. It becomes impossible for a WE to move cautiously across a friendly trench line. They must take a full move and a normal difficult terrain check. Is that intended or desirable? I personally don't think so.
Picture an infantry screen in front of a Warlock titan (different formations and different WE speed). The enemy engages from 5cm in front of the infantry. The titan cannot countercharge to contact with the enemy because there is not enough space to allow the titan's base between the friendly infantry and the attackers. It's not poor placement or bad tactics to use an infantry screen. It's something that should be a reasonable tactic, but instead of being a reasonable thing to do it hinders the titan.
A smaller WE also becomes more maneuverable. After all, a 3cm wide model with 5cm charge chan fully clear 2cm, while a 5cm wide WE could not clear anything. There's an incentive to make proxy Gorgons (in this case) as small as possible because, unlike the relatively minor differences on the infantry bases, this is potentially huge.
And even if you do that, it doesn't quite work. For example...
Onyx wrote:
As I said before, the friendly infantry are not being barged in this case because that would be against the rules. They are being moved to maintain the CC fight they are already engaged in.
Nothing in the rules indicates CC must be maintained except between the WE and the enemy units. By your own admission, you are just making this up because you think it's the only fair way to do it (and I agree it's more fair than the alternative).
Further, once the enemy are in contact with the WE, their "2 units in base contact" quota is filled. Moving friendly units back in contact with the enemy is just a made-up idea that arguably contradicts another "hard" and explicit rule.
And yet, what you propose seems reasonably fair under the circumstances, so you are arguing that some "new" rule should be implemented. But that puts us back into the "we're really just making it up as we go" realm.
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Edit: Sorry. Grammatically terrible. I'm short on time today, so bear with me.