Did Lampard really tighten things in defence? He only did it for Sevilla and United after the Southampton debacle.
The biggest difference between Lampard and Tuchel has been the tactical acumen the latter has brought to the team (the lack of tactical acumen was arguably the biggest problem with Lampard). We looked okay under Lampard until we started playing a bunch of top half teams in December. We just looked tactically clueless in pretty much every game and all the flaws with our team shape on and off the ball etc were horribly exposed. Tuchel came in, chose a formation and has given us a tactical organization, a solid foundation not seen since the days of Conte. We now know when/where/how to attack, to defend, to press and counter press, individually and collectively. Obviously, there's still room for improvement but at the very least, we don't look like headless chickens any more the minute we come up against a half decent side and the record so far speaks for itself - we've won 2 of the 3 games against the current top half teams under Tuchel compared to just 1 win out of 9 under Lampard this season.