Strangely I agree with most of what DaveK said. I think it's safe to say most of us were okay with Martinez's tactics when we were winning games last season. It seems teams have figured out that we struggle if they press us high up the pitch, and defend compactly once we're in the opposing half, and many on here are criticizing Martinez for failing to adapt his tactics to something that every team we face appears to be doing.
But the high-press/compact defense style of play isn't really conducive to scoring goals against us unless our players make individual errors; incidentally we made very few individual errors as a team last year and have made several almost every single game this year. Last year we were able to pass the ball out the back even when teams pressed us, this year we can't, and for me that's on the players and not the manager. We're also failing to break down teams when they're defending in their own box (I too am frustrated with the balls played into Naismith / Lukaku that are then passed back to midfield), but it's hard to draw teams out of the box when they can so reliably depend on our own mistakes to create goals.
I'm not saying Martinez is perfect, I think he has miscalculated several times this season, and I still blame him for not bringing in a world class centre half in the summer. But I think he's more adaptive than people recognize. He's changed his usage of substitutions across the season to improve their impact, and managed the squad decently at a time where we've been horrifically plagued with injuries and loss of form. I thought he used Baines effectively in the left-centre-mid / attacking mid role against Newcastle, even though it didn't work out on the day.
To the original question, there are definitely things we can moan about, because we've lost 8 games ffs. We desperately need to sort out the defensive errors, and we need to figure out (to borrow RM's words) "clever" ways to break down the opposition in the final third. But there's a difference between moaning and blaming, and while it's natural to try to blame someone or something when things don't go our way, the tendency is rarely to ascribe blame in a logical or correct manner.
We've still got half a year left and an outside chance at the Champions League via Europa, COYB!!