I miss when it was just the Original Team Arrow! I preferred it when Oliver went out on missions solo! It made everything seem more intense than it is now because he has 50 other people as back up.
Even when it was Oliver and Diggle, they were usually in different areas - Oliver taking on the main bad guy and Dig often keeping his distance as a sniper and/or taking on surrounding security. This also meant they had a good reason to continue dialogue when separate - they often needed to be the eyes and ears for the other - so it made sense in a narrative purpose.
After the end of season 3 Diggle was by far the most experienced in the field so he needed to lead Laurel and Thea in the field. Dig wasn't so much a mile ahead as much as he was a light year ahead. I think that's what made Oliver, Dig and Sara effective in the field, they were all competent and equally able to handle their objectives.