ancientvaults
Explorer
When it comes to miniscule CR differences like 1/3 vs. 1/2, the ssue isn't if the encounter will kill the party or be a cakewalk. The issue is that, in this case, the enemy with (effectively) more hp and that dishes out more damage gives less XP than the other monster. At least that'd be the issue to me. It doesn't really matter much that the hobgoblin fighter has a bunch of extra nice things. If you're using them for a straight up combat encounter with the party (which I think is a fair assumption for these monsters; hobgoblins might have a use for a ambush I guess, but you can modify the xp for those kinds of fights for "situational advantages" anyway), the damage and staying power is by far the biggest measure of threat, IMO.
I agree heartily. If I am going to throw, say goblins at a party now I will make specialized goblins in groups, adjusting x.p. along with other additions, and then mixing them together.
For example, three goblins attacking an individual may include an archer, a heavy weapons guy and a quick stabby guy. Add in more for more players and run with it.