You need to be aware of the license policy doing this. You need a separate license for each installation.
Axapta does not support replication of databases; you can work with export/import of a given company. This process has a couple of setbacks; Axapta uses a Record ID to identify a single record unique in the Company (in Version 3.0 in 2.5 in all Companies). A SQL database can not enforce this ID across multiple tables, this will not be a problem during daily operation, but on data import a table is created containing all record ID's to convert all references within Axapta. If you have the same record ID in two tables only the first record will be imported. The import/Export function does not give you the robustness you need to consolidate controlling date on a regular basis. If this is the only solution for your company, you should create a solution yourself.
In your case I would stay with the Citrix server. Using a Citrix server gives you a couple of advantages operating and supporting the solution. You would have a central backup of the database. You do not need a IT-Professional on each site to operate Axapta.
Using Citrix will give you a couple of challenges within Axapta, but non that has not been solved in Axapta. To control access to each company you need to have the license «Domains». The second problem concerns backup and recovery of a single company within Axapta, as you have only one database for your entire system. Microsoft has published a technical white paper on this issue; you will find the document on the Axapta 2.5 Installation CD in the documentation folder.
This is of course my humble opinion.