VMC or IMC? If former, there are other options. Reduced Separation in the Vicinity etc. (In the video, the visibility looks poor...) It all depends on just how tight it has got and what the circumstances are. If it has got TIGHT, then the controller should have updated everyone's situational awareness and have had a plan B based on local knowledge. Are "Land after the departing" criteria permitted? An unstable approach GA might be something that could catch the ATCO out as being unexpected. (But again,. was it gusty/cross winds/windshear around etc.) Always difficult to tell from a video but might seem that in this case controller made a sound judgement call. I'd be reluctant to give a shedload of extra non-standard instructions (rate of climb/turn etc) to a crew in a high workload situation handling a go around because of an unstable approach. Lots of variables depending on conditions, local procedures, circumstances etc.