An era ended for Glasgow Warriors in Dublin on Saturday.

To those who decreed that it was time for change at the Scottish club it could not have come at a better place, serving as a reminder of what the club's supporters are entitled to expect.

Leinster, Glasgow's hosts for Saturday's RaboDirect Pro12 play-off at the RDS, are champions of Europe – and favourites to retain their title this weekend – but that was far from the case when Michael Cheika turned up to coach them in 2005.

The Australian arrived at a club that boasted some of the best individual talents in Europe, but which lacked the collective will to make the most of it, having failed to win a trophy since they had claimed top spot in the inaugural Celtic League in 2001/02.

In his first season in charge, the ante was upped spectacularly by a crushing semi-final defeat by their provincial rivals Munster on their way to winning the Heineken Cup and by finishing runners-up to another Irish province, Ulster, in the Celtic League.

By the time Munster had won a second European title at the end of the 2007/08 season, Leinster's Celtic League win was scant consolation for Dubliners and the pressure was on, yet his employers had the vision to retain faith in the man who had taken on a difficult project.

They were rewarded in remarkable style the following season when the team based in the capital replaced Munster as European champions.

One year later, after he had led the side to a third successive Heineken Cup semi-final appearance, as well as to the inaugural Celtic League Grand Final, Cheika made the decision to move on. He seemed to be the hardest of acts to follow, having transformed Leinster from stylish failures into a hard-edged team of winners, and the Irish RFU's choice of replacement looked a strange one.

Joe Schmidt had been assistant coach at Clermont Auvergne, very much the sort of perennial underachievers Leinster had been before Cheika's arrival and, in his first few weeks, there were real fears that he would allow his new charges to resort to bad old ways.

The side lost three of its first four matches under his charge but, since then, Schmidt's team have lost only seven more of 60 in an astounding run which has taken them to the finals of both competitions they contest in each season, having won a second Heineken Cup last season, a competition in which they have lost just one of the 17 matches on Schmidt's watch.

The New Zealander has taken them up another level, from having joined Europe's elite to establishing themselves – irrespective of what happens as they seek to patch up their battered squad over the next 13 days – to the outstanding outfit in the continent.

Scottish rugby's aspirations and expectations must, as a result of a history of failure in the professional game, operate on a very different scale, but the same basic principle applies. Perhaps even more so because, far from being forced into replacing their head coach, as Leinster and the Irish RFU were, some Scottish Rugby Union executives decided they knew better than the vast majority in the sport and chose to sack Sean Lineen and replace him with Gregor Townsend.

Warriors supporters are, then, entitled to expect that, as was the case at Leinster, the transition will not only be seamless, but that they should immediately be improved, particularly given the additional quality of players Lineen recruited before and after being given the shock news he was leaving. To the bargain-basement squad that Lineen honed into one capable of reaching the RaboDirect Pro12 play-offs twice in three seasons has been added considerable firepower.

This at a time when, within the Pro12, the Welsh provinces are in transition, Munster and Leinster's best are beginning to look as if the battles of a decade and more are taking their toll and Italian rugby remains callow in provincial competitive terms, set as it is, to replace one of its franchises this summer.

Furthermore, the Pro12, in terms of producing Heineken Cup contenders, has proved itself a far superior competition to England's Aviva Premiership and even the French Top 14.

The minimum that would have been expected of Lineen next season would have been to reach the Pro12 Grand Final and a Heineken Cup quarter-final, so the SRU's belief that they have replaced him with someone better means that, just as Schmidt has done, even more must now be expected.

The circumstances of Townsend's appointment resulted in bemused onlookers coming up with theories as to what he has done to deserve it after three years of failure as Scotland's "attack" coach. Prominent among those conspiracy theories is that the situation was engineered to see off two birds with one stone: Andy Robinson, Scotland's head coach and a powerful figure within Murrayfield, may have off-loaded an ineffective assistant at the same time as removing the most obvious threat to his own position.That is distinctly plausible if we are to presume that Robinson was to have thought through any such theory, as Townsend's switch has left the Scotland coach in a no-win position.

Should Townsend succeed with Glasgow it will be clear that, as some of his media supporters claim, he was thwarted in his thinking with the national side by the head coach.

It is, of course, easy for someone in an assistant's role to claim he would have done things differently if allowed to do them his way, but Townsend will now get his way on the big calls and we will see what he can do.

If he takes Glasgow Warriors to new heights, it will underline that his methods are much better than has been indicated by any evidence to date, and just how poorly Robinson is performing as Scotland's head coach.

If he does not, it will demonstrate that those, including Robinson, who recommended him for his new job, have simply done further damage to the Scottish game.