Personally I haven't got an issue with Frank. The fact we didn't give him the right tools clears his time here for me.
That said if he can't get results at Chelsea it shows that whatever we may have given him it still wouldn't have been enough. However had we got a striker in January 1st it may have pulled us up from the death spiral, lifted everyone, gave Lampard a bit of zip and one of those defeats turned into a win. If that happens and suddenly a bit of confidence comes back instead what happened in reality where we kept losing and chunks were eroded from the team and himself leaving him not knowing which way is up to get out of it.
How much of that right now is Lampard being found out as a manager or if Everton broke him, like above with the forward he never got, we'll never know. Hopefully he starts winning again for his sake.