It's really simple... It means something exceeds in certain quality by a little bit. You can roughly translate it to "a little too <em>adjective</em>" or "a little <em>adjective</em>-er than it used to be"
This examine is a little harder <em>than it used to be</em>
His criticism is a little too harsh
Or you can simple rephrase it “...了一點” = “比較...”
这个语法难<s>了一点儿</s> = 這個語法<em>比較</em>難