is checking 'allintitle' competition still relevant in 2015?

My original SEO course, 4 years ago, mentioned checking allintitle competition, then find relevant low competition keywords and place it on your own title as well as mention it as many times as possible without obviously keyword-stuffing.

As things tends to change so quickly when it comes to SEO, I wonder if this technique is still relevant?

Yes it still holds importance...one my colleagues makes sure everytime that his title is unique and guess what this guy is really good at ranking content...people talk about ranking websites but this guy ranks content and one thing he always make sure in his articles is that he covers every aspect of it.

It's an obsolescent method of evaluating competition. The best way is to analyse the top 10 ranking sites for the keyword. This is what works in 2015 and beyond.