Wicket をMavenで取ってくるなら、

Wicket のサイト http://wicket.apache.org/ に書いてあるように、Maven取得用のpom.xml に書く dependencywicet-core だけにすると、
他に、
wicket-parent
wicket-request
wicket-util

を取ってくる。

extensions や、ioc とにかく全部取ってくるなら、
    <properties>
       <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
       <wicket.version>1.5.1</wicket.version>
    </properties>
    :
    :
<dependencies>
    <dependency>
        <groupId>org.apache.wicket</groupId>
        <artifactId>wicket-core</artifactId>
        <version>${wicket.version}</version>
    </dependency>
    <dependency>
        <groupId>org.apache.wicket</groupId>
        <artifactId>wicket-auth-roles</artifactId>
        <version>${wicket.version}</version>
    </dependency>
    <dependency>
        <groupId>org.apache.wicket</groupId>
        <artifactId>wicket-request</artifactId>
        <version>${wicket.version}</version>
    </dependency>
    <dependency>
        <groupId>org.apache.wicket</groupId>
        <artifactId>wicket-datetime</artifactId>
        <version>${wicket.version}</version>
    </dependency>
    <dependency>
        <groupId>org.apache.wicket</groupId>
        <artifactId>wicket-devutils</artifactId>
        <version>${wicket.version}</version>
    </dependency>
    <dependency>
        <groupId>org.apache.wicket</groupId>
        <artifactId>wicket-extensions</artifactId>
        <version>${wicket.version}</version>
    </dependency>
    <dependency>
        <groupId>org.apache.wicket</groupId>
        <artifactId>wicket-guice</artifactId>
        <version>${wicket.version}</version>
    </dependency>
    <dependency>
        <groupId>org.apache.wicket</groupId>
        <artifactId>wicket-ioc</artifactId>
        <version>${wicket.version}</version>
    </dependency>
    <dependency>
        <groupId>org.apache.wicket</groupId>
        <artifactId>wicket-jmx</artifactId>
        <version>${wicket.version}</version>
    </dependency>
    <dependency>
        <groupId>org.apache.wicket</groupId>
        <artifactId>wicket-objectsizeof-agent</artifactId>
        <version>${wicket.version}</version>
    </dependency>
    <dependency>
        <groupId>org.apache.wicket</groupId>
        <artifactId>wicket-util</artifactId>
        <version>${wicket.version}</version>
    </dependency>
    <dependency>
        <groupId>org.apache.wicket</groupId>
        <artifactId>wicket-velocity</artifactId>
        <version>${wicket.version}</version>
    </dependency>
</dependencies>