Holyrood's Justice Committee has been scrutinising the package of reforms, put forward after a review of the civil courts concluded the service they provided to the public was "slow, inefficient and expensive".
While it backed the general principles of the Courts Reform (Scotland) Bill, committee convener Christine Grahame said they were "not convinced" some of the changes would achieve the desired results.
Ms Grahame said: "There can be no doubt from the evidence we heard that reform of the Scottish civil court system is long overdue.
"However, our committee is not convinced that some of the measures in the Bill will necessarily achieve what is hoped."
She said the committee believed increasing the threshold for cases at the Court of Session was a "step in the right direction" but added concerns had been raised about whether changing this from £5,000 to £150,000 was too large.
The move has been proposed in a bid to free up the Court of Session for the most complex and serious cases, and to help make the civil justice system more economical.
In their report, MSPs voiced doubts about the "robustness of the data on which the proposed limit of £150,000 is based", stating the evidence for this "seemed anecdotal".
They said: "On balance, we consider that the proposed increase in the privative jurisdiction of the sheriff court from £5,000 to £150,000 may be too great a leap. We therefore recommend that the Scottish Government introduces a lower limit."
The Bill also plans to set up a specialist personal injury court, as part of a package of measures to ensure that cases are heard in the most appropriate courts.
But as people will still have the option of raising such a claim in their local sheriff court, the committee called on the Scottish Government to provide "further clarification as to how this will work in practice, along with an estimation of the number of cases expected to be raised in local sheriff courts and in the new court".
MSPs also questioned if sheriff courts and the personal injury court would be able to take all of the cases that would previously have gone to the Court of Session and noted concerns that had been raised that no new resources have been made available to implement the "extensive reforms set out in the Bill", adding they "remain to be convinced that the new procedures will have no financial impact overall"
The committee called for assurances that there would not be a "substantial rise in the level of court fees to pay for the reforms in the Bill".
Ms Grahame said: "Improving access to justice is a key part of the Courts Reform (Scotland) Bill.
"Freeing up the Court of Session to deal with the most complex and serious cases is a step in the right direction.
"However, raising the monetary threshold from £5,000 to the proposed £150,000 raised questions about whether this is too great a leap.
"Not only would these reforms perhaps restrict access to counsel, but there are concerns about the capacity of sheriff courts to deal with the increase in cases.
"Our committee recommends that the Scottish Government give serious consideration to lowering the monetary limit."
A Scottish Government spokeswoman said: "The Scottish Government welcomes the report of the Justice Committee and are pleased that the committee agree with the general principles of the Bill.
"It is important to ensure that any new limit set for cases being raised in the Sheriff Court reflects the fact that at present too many low-value cases are being raised unnecessarily in the Court of Session. This results in increased costs for all parties involved and deters other kinds of litigation from being raised there.
"It is also important to ensure that the limit allows a suitable amount of business to transfer to the new specialist personal injury court. We consider this a more effective and efficient way to deal with such cases than the current situation where personal injury cases make up almost 80% of cases raised in the general department of the Court of Session.
"The Scottish Civil Courts Review recommended £150,000 as the appropriate limit for the exclusive competence of the Sheriff Court to meet these aims, and the Scottish Government agrees, which is why we consulted on that level and included it in the Bill.
"We believe that there is sufficient capacity in the Sheriff Courts to absorb the expected transfer of around 2,700 cases from the Court of Session.
"This was also the view of the Lord President and the chief executive of the Scottish Courts Service when they gave evidence to the Justice Committee.
"Indeed, recently released statistics show that there has been a substantial reduction in the number of civil cases being heard at Sheriff Court level - a drop of around 8,000 cases (9%) between 2011-12 and 2012-13, and a drop of over 50,000 cases (41%) since 2008-09.
"As stated by the convener, improving access to justice is a key part of the Bill and we will consider the recommendations of the Committee to ensure that the Bill achieves this."
James Wolffe QC, the Dean of the Faculty of Advocates, said: "I am pleased that the concerns which the faculty and others have expressed about certain aspects of the Bill have been recognised.
"I look forward to continuing to work with ministers and others towards achieving an improved civil justice system for Scotland which allows ordinary litigants to secure the highest quality representation.
"We believe that there are measures in the Bill which will - along with all the other work which is being done to reform civil justice in Scotland - lead to an improved system and which ought to be supported."